I’m getting a number of these:

As someone who was at the game last night, it’s interesting to notice
that the article fails to mention that the Vice President didn’t get
booed until after most of the fans cheered for him. As a frequent
attendee at Yankee games, being a season ticket holder, I can speak from
experience when I say that it’s far easier to project more sound booing
than clapping and cheering, not sure what the acoustical reasons are for
this. Needless to say, the majority of the crowd was cheering first.
In hindsight, it may have had something to do with all those Boston fans
being there, I’m sure that more than a few are Kerry supporters.