Originally Posted by The Saint
That's an Ontario bylaw.
It's an Ontario law with regards to selling air guns. No other province has a law in the books like this one. However, the thread started by Illusion asking whether or not 18 is legal age to own airsoft has a lot of good info in it. In that thread, Greylocks points out all the particular federal laws regarding ownership of such items, and the reasoning that 18 is the required age for ownership. The whole subject is an ambiguous grey area mess, but the reasons he gives are about as good as it gets.