Frosty one time rolled over by way of greeting for a very excited rottweiler, who lunged forward and chomped her on the foot so hard she yelped and then limped for about 10 minutes afterwards. And rotty owner wanted to have a look - paw wasn't bleeding and there was no way I was going to let him near my dog for a look while he was still holding his rotti. Stupid man.
I don't let them say hello now, ever. And I won't until I see some sign that his dog can be calm around dogs it doesn't know well.
It's still in our class, and it still lunges at other dogs to bite. And we're supposed to do weaving in and out around it. There are several dogs that cannot do this task without trying to attack other dogs. There is one dog that the owner fully acknowleges can't do it, so they don't weave, they walk at a safe distance that her dog can cope with. Why the other owners are in denial - I don't know.
Frosty does play "bitey face" as Ian Dunbar calls it, with some of her friends and it can look fearsome but nobody is yelping or screaming or running away in fear. So there are definitely good nips and bad bites.
I try to keep Frosty away from dogs that are out of control lunging at the end of the lead.