As kids, most of us conducted careful on-site inspection (and some war games) at neighborhood construction sites. Because of this childhood propensity-Contractor beware!
Although a 1967 Colorado Supreme Court decision ruled that a minor child and his parents could not recover for damages to the child suffered in a fall while trespassing at a construction site [Garel v. Jewish Community Centers of Denver, 163 Colo. 110, 428 P.2d 714 (1967)], there is no SITE assurance that more modern legal philosophies might not result in changes to that rule.
The legal doctrine involved is popularly called "attractive nuisance under which a property owner or occupier may be liable for damages to children attracted to the property by some unusual feature appealing to a normal child's inquisitiveness.
Indeed, a recent Illinois appellate court case ruled that suit on behalf of a ten-year old child could proceed to trial where the claim involved a child's injuries suffered from a construction site fall. Novak v. C.M.S. Builders and Developers, 404 N.E.2d 918 (Ill. App. 1980).
Rather than pondering the legal issue or philosophy involved, the prudent contractor should give careful consideration to jobsite fencing. This may avoid not only the risk of liability (which may otherwise be covered by insurance) but also disruption of the work and time wasted if an injury occurs and suit follows.
Reviewing the fencing question in light of local building codes, general safety requirements, specific contract requirements, insurance aspects and good common sense may avoid unnecessary problems for the astute contractor.