I think perhaps an age limit would be a good idea...but hard to enforce. Too many parents are too focused on their kids being the center of their world to realize that they're not the center of everyone else's too.

I'm recalling the incident a few weeks back where a mom had a young son holding the leash to their husky. The kid couldn't control the husky, and I was out walking a dog aggressive dog on-leash and wound up wading into a dogfight. What did the idiot mom do but hand the leash righ tback to the kid. Unfortuantely it's the people like that who would flat-out ignore an age limit IMO...