Where a municipality provides a recreational facility for use by children under 12 years of age, thereby creating a potential risk of harm, it owes a legal duty to take reasonable steps to prevent that risk from materializing through proper supervision and/or access control. This duty exists independently of parental supervision, particularly where parents are prohibited from entering the facility themselves. The existence and scope of this duty is determined by considerations of reasonableness, public policy, and constitutional norms (particularly section 28(2) of the Constitution requiring children's best interests to be paramount). Where it is reasonably foreseeable that uncontrolled access to a water slide by multiple young children will result in pushing, bunching, and potential injury, and where simple supervisory measures could prevent such harm without imposing an intolerable burden, failure to implement such measures constitutes negligence. A debt owed to a minor child cannot be set off against contributory negligence of the parent when that parent sues in a representative capacity on behalf of the child.