Britney at the Garden
According to the security guard, this is just her "dancers". I think this decoy bus is the real bus and this is actually video of Britney leaving Boston, but whatevs.
I have some advice: if you ever want to incite a mini-riot in Boston, yell "OH MY GOD IT'S BRITNEY SPEARS!!!" after her concert as a bus pulls out. You'll get a crowd swarm around in 2.2 seconds.