Yikes! There is something really wrong going on with that dog. I do rescue and have fostered dozens of pits and pit mixes, and I've never had a single one that would snap at people. In fact, I often tell people that most make horrible guard dogs since they'll often roll over on their back with happy wiggles when a stranger walks in. Are her dogs all spayed or neutered? It is spring and dogs are coming into heat. Hormones are the only things that I can think of that would make a normally friendly dog start acting aggressive. Her dogs definitely all need to be spayed or neutered if they're not anyway as we have a serious dog overpopulation and it's especially bad with pits and pit mixes and then that's compounded by the fact that there are lots of laws that discriminate against them. But seriously--I've known pit bulls that had been shot, beaten, and set on fire that would still lick you to death.
As far as people who let their dogs run wild in their house--that drives me crazy! This past weekend I went to tour an animal sanctuary where over 100 dogs lived. They all ran loose on the 150+ acre property, but they still all knew better than to jump up on people and were enjoyable to be around. It really bugs me when people don't know how to train their dogs and it makes the poor dogs unenjoyable to be around.