Out of curiosity...how much are the tickets going for in Boston?
The reason I bring that up is because here in LA, the tickets price out a good portion of the type of people that generally do this crap. You won't see that much more than some ball-busting, as the C's fan in San Diego mentioned.
However, in '08 they had a "viewing party" at Staples for Games 1 & 2, and it only cost $15 to get in. I went to Game 1, and there were a few Celtic fans there. This was the game where Pierce heroically overcame his devastating injury (

) and helped the C's pull away in the 2nd half. There were a couple of fights in the stands during the game, and when leaving the arena it got worse. Just hoards of people intimidating the Celtic fans whenever they saw them. I even saw them doing it to a woman.

I tried to intervene, but got shouted down.
Anyway...all fan bases have that. Lord knows we have enough gangbanger Laker fans that do this crap.