So who lets their dog run free off the leash in a park where it's clear that dogs are welcome, but ON their leashes?

Today Smokey and I went down to the park - the first time out for him on his 30 ft lead. Well, we walk into the park (he's not 30 ft out yet) and I see an adult dog (he was a pit/mix) about 1/2 qway down the grass. The dog runs over to Smokey and at first things were OK but then the other dog snapped and started barking and rolling Smokey around. The owner calls from 1/2 across the park "Come here now!" Uh, thanks.

Basically I'm just pissed cuz I think if you're gonna let your dog off the leash at a place where they are supposed to be leashed you should at least like, be WITH your dog. But whatever, I got over it after the dog got up on Smokey again and then finally ran away.

But then are walking and Smokey starts going towards them (her dog still not on a leash) and she says "He's really friendly." OK. Fine. So we go over and I've got Smokey right by me... things are chill... I let him go a little further... things are OK... then the dog snaps again and she goes "Boy! aren't you in a mood today?!"

Whatever.

But we did run into a Bermese Mt. Dog - I'd never seen one before. So pretty! I could never handle all that hair , though.
His name was Nepoleon cuz he's small for his breed.

ANYWAY - so if you guys let your dogs off their leashes where they aren't supposed to be, aren't you afraid your dog will be "in a mood" and snap?