Cocktail sausage

You know those lil' sausage dogs? Well, today on our walk there was a cocktail sausage dog, he was that lil'. We was walkin' by this house & in their garage was these lil' dogs. The fuzzy one was loud & rude. He was makin' all kinds of noise. Lexie did her abrupt stop, where she faces the noise w/one paw up, & you can tell she's thinkin' about tellin' 'em off. But I guess she decided that it wasn't worth the trouble, he was stayin' in his garage & was kinda small, anyway. 
So, we continue on...when all a sudden..out comes this tiny lil' brown weiner dog, waggin' his tail. He comes right up to me. Ok...I'll give him a sniff. We get nose to nose, he wags his tail some more, I try not to step on him...but I gotta go. I mark the bush by his driveway...kinda like a callin' card..and we continue on.

 Uh oh...me & Lexie both stop & look back...he's following us. He's not supposed to do that. Where's his people? Nowhere in sight. Dad says, he'll get bored & go home. We continue on some more. I stop, again & look back. He's still followin' me. I leave some marks here & there (kinda like bread crumbs, he can follow them back to his house is what I'm thinkin'). After about 4 or 5 houses...he looked like he was headed back.

Two things I don't understand....

One-why was he just loose to run around? He was so little,  an' his legs were so short...they just looked like feet, no legs there at all...how could he get away from any danger?  There's no way he could outrun anythin'..an' he's snack size.   

Two- Why do lil' dogs always want to pal around w/me & the big dogs always want to challenge me? I just don't get it. Lexie thinks it's hilarious