Irregardles of whether this is specifically mentioned in the new WT talmud for elders - in my experience if the B-day celebrators did not repent and say they were sorry convincingly enough to the prosecuting elders, they could very easily create reason enough in their minds to DF them.
Many DFings occur based simply on local congregation politics and just how rabid a body of elders is on the case.
I have seen only one witness ever DFd for drunkenness, for example. She was an inactive person who was disliked by some elder's wives. I have, however, seen several extremely drunken elders who stayed as drunken elders forever - I suppose until they died.