When the legislature codifies principles of common law, it can be perceived as a pruning of the living tree, helping to direct the law in growing in a specific direction, and sometimes preventing it from growing in other directions entirely.
The area of occupier’s liability is a perfect example of this. The Supreme Court of Canada conducted an exercise of statutory interpretation over the Occupier’s Liability Act, which was created in 1980, in the 1991 case of Waldick v. Malcolm. At the time, provincial legislatures across Canada were attempting to consolidate this area of law in their respective jurisdictions.
The Act made a specific point of overriding the existing common law principles,
In this Act,
(a) a person who is in physical possession of premises, or
(b) a person who has responsibility for and control over the condition of premises or the activities there carried on, or control over persons allowed to enter the premises,
despite the fact that there is more than one occupier of the same premises; (“occupant”)
“premises” means lands and structures, or either of them, and includes,
(b) ships and vessels,
(c) trailers and portable structures designed or used for residence, business or shelter,
(d) trains, railway cars, vehicles and aircraft, except while in operation. (“lieux”)
Common law duty of care superseded
this Act applies in place of the rules of the common law that determine the care that the occupier of premises at common law is required to show for the purpose of determining the occupier’s liability in law in respect of dangers to persons entering on the premises or the property brought on the premises by those persons.Subject to section 9,
Justice Iaccobucci stated in this case,
In general terms, the Act sets out the duty of care owed by occupiers of premises to persons who come onto those premises and specifies certain exceptions to the prescribed duty of care. As this appeal is the first involving the Act to reach this Court and as several provinces have similar statutory regimes, it is important to clarify the scope of the duties owed by occupiers to their visitors.
In analyzing the Act, the Court looked at the 1972 Ontario Law Reform Commission Report on Occupiers’ Liability,
These extracts emphasize that one of the principal purposes of the legislation was to replace the somewhat obtuse common law of occupiers’ liability by a generalized duty of care based on the “neighbour” principle set down in Donoghue v. Stevenson,  A.C. 562. Blair J.A., at p. 722, also quoted Professor Fleming from The Law of Torts, (7th ed. 1987), at p. 450, as to the success of the reform brought to this area of the law by occupiers’ liability legislation:
Its central feature was to abandon the timorous distinction between categories of entrants and subsume the law of occupiers to the unifying principle of a “common duty of care”. The dearth of reported decisions over 25 years of operation bespeaks success in at least one of its objectives.
Despite these reforms to the duty of care, the Court was not willing to allow the legislation to subsume the common law defences of occupiers’ liability, as they were conspicuously absent from the section of the Act quoted above,
I am of the view that the Act was not intended to effect a wholesale displacement of the common law defences to liability, and it is significant that no mention is made of common law defences in s. 2. Reinforcement of this view is found when one asks why this area of law should entail a defence other than volenti which is applicable to negligence actions generally. There does not appear to be anything special about occupiers’ liability that warrants a departure from the widely accepted volenti doctrine.
[emphasis in the original]
Almost 25 years after Waldrick, these principles were recently revisited and affirmed by the Ontario Court of Appeal in MacKay v. Starbucks Corporation.
The facts of this case are not remarkable. The plaintiff experienced injuries as a result of a slip and fall that occurred on a sidewalk or patio that was adjacent to the Starbucks.
Although the plaintiff had dismissed her action against the city, the landlord and the landscape contractor the parties could not agree as to,
(a) whether the patio was a common element or common area of the shopping centre that the landlord had a contractual obligation under the lease to maintain for ice and snow,
(b) whether Starbucks was an Occupier of the patio, or
(c) whether Starbucks was an Occupier of the city sidewalk.
The definition of “occupier” in Ontario is rather broad, wider than other provinces such as British Columbia. In Ontario, it is sufficient that a person have responsibility and control over the conditions of the premise. The legislature does not legislate in vain, and if physical possession is also necessary for liability, the definition of “occupier” under the Act would not include s. 1(b).
On this basis, the trial judge concluded that the manner in which the Starbucks built its fence and patio, making a path over the sidewalk which led directly to the side door, and by monitoring the conditions of this pathway, they assumed a sufficient level of possession and control over this area.
The Appellant attempted to rely on the Court of Appeal’s decision in Bongiardina v. Vaughan to support the proposition that by sanding and salting a municipal sidewalk, an adjacent landowner or tenant is not automatically liable for that sidewalk. The court rejected this argument,
 …In Bongiardina, the court framed the issue in terms of whether there was a common law duty on a property owner, in that case a residential homeowner, to clear sidewalks adjacent to the property. The court found no such duty. The court explained that clearing snow and ice from sidewalks and fixing potholes is the legal responsibility of the municipality, not the homeowner, subject to two exceptions: 1) if the homeowner is deemed to be an occupier of the sidewalk under the Act by assuming control of it, such as occurred in Bogoroch and Moody; or 2) if the homeowner allows something from his or her property, such as water, to flow off it and onto the sidewalk causing injury to persons.
 Bongiardina, therefore, simply reiterates that a property owner or tenant will not be deemed by the Act to be an occupier of an adjacent sidewalk merely by clearing that sidewalk of snow and ice, whether in compliance with a municipal by-law obligation or otherwise. More will be needed to meet the definition and impose civil liability…
The court affirmed that determination of occupier status requires a case by case analysis on the facts in the context of the Act. Some of the factors that courts will review may have some storeowners liable for portions of the sidewalk adjacent to their store, but there is no blanket rule which can be applied. The court affirmed the trial judge’s finding that the Starbucks was an occupier, and dismissed the appeal.
As an alternative cross-appeal, the Respondent raised the issue that if the statutory duty under the Act did not apply, that the common law duties would proceed. The court addressed the question as to whether the common law duties of care had been abolished due to the Act by adopting the following statement in Bongiardina,
 The question then becomes: is there a common law duty on the owner of the property to clear snow and ice from public sidewalks adjacent to the property? In my view, the answer to this question must be “No”. Although the “neighbour” principle from Donoghue v. Stevenson,  A.C. 562, 101 L.J.P.C. 119 (H.L.), has been expanded in recent years to cover a myriad of new relationships, it would stretch it too far if it was applied in the circumstances of this case. A homeowner has a duty to ensure that his or her own property is maintained in a reasonable condition so that persons entering the property are not injured. If the homeowner complies with this duty, he or she should be free from liability for injuries arising from failure to maintain municipally owned streets and sidewalks. The snow and ice accumulating on public sidewalks and the potholes on the street in front of the house are the legal responsibility of the municipality, not the adjacent property owner.
The Court of Appeal in McKay noted that other common law duties for adjacent landowners who are not occupiers may apply, but concluded,
 What is clear, however, based on s. 2 of the Act, is that there is no general common law duty of care, based on proximity principles, owed by an adjacent property owner or tenant in respect of sidewalks that abut that person’s property.
The only duty is the statutory duty that is owed by a person who meets the definition of occupier under the Act.
As Klar writes in Tort Law at p. 627: “[i]t seems irrefutable that the legislation was intended to be exclusive and comprehensive, in so far as the liability of occupiers is concerned.