Has anyone ever had band slippage from PBing????

Never heard of it. PBing, after all, isn't vomiting. It's simply regurgitation and takes place in the esophagus rather than the heaving that takes place when you vomit from your stomach. If you have any doubts, talk to your doctor.

I havent had a slip but I have had a bad pb episode cause stomach swelling where I keep pb'ing more, which causes more swelling and further pb's, until I eventually needed an emergency unfill.

While it is true that pb'ing is not the same nor as dangerous as vomiting, it can still cause some damage.

If you are constantly pb'ing over an extended period of time, which can be caused by keeping the band too tight, you can eventually slip. A too tight band can cause slippage and excessive pb'ing is a symptom of a too tight band. Pb'ing may not have caused the slip in and of itself, but being too tight can absolutely contribute to it.

There have been many threads where people have slipped and being too tight for many months beforehand is mentioned frequently.