It's not quite as bad as it once was, I saw about 34,012 fights at a game in 2000. In the late 70's, it actually might have been even worse, but there was less security in those days...

Peckerhead fans in a mob, regardless of their team loyalty, emboldened by liquor, always have the potential for danger.

The Yankee-Sawk media-fed rivally has some basis of truth if certainly overrated by the east-coast media machine- but yes, this one's four stars.

Sad but true: there's few more dangerous gangs than ten white guys in red attire with Boston accents deciding that they don't like you at Fenway. I've seen it on more than one occasion, and it's ugly, though to be fair to the cops HistoryFan is wrong about the police: they do their best but generally take a few knocks themselves. Outside the stadium, on an ordinary Boston street, any number of people wear Yankees caps with impunity, but when a few Fenway-goers are fully liquored up, you might as well be in Raider Stadium's "Black Hole."

Considering that everyone in Boston is a rabid Red Sox fan, I doubt the police and security will help you out when you get mobbed.