Dogs behaving badly

For almost two weeks now, Jorge and I have been petsitting Winston, my sister's dog. We take him out, on a leash, in our yard, to do his business. What bothers me, is the dogs across the street start barking like crazy, like we're on their property! Hello, we live here, you live there. The reason is probably because their owners let them loose to do their business, and for some reason they've been doing it on our property. Jorge caught one of the little buggers the other day.

I would never let my dog do that. Hmph.