"It sure seems an intentional act to get the majority of fans to reside in one place so that the actors can sneak out another way. And IF that is the case, then it's a bit of foul trickery."
Just to play devil's advocate, what if the actor requests for this to happen out of concern for their safety or for a personal reason that wouldn't be known to said fans? Big movie stars having stalkers or people who endanger them or make them feel uncomfortable is hardly a rare phenomenon. Yes, it's an annoyance to those who wait, but the access people have to their favorite Broadway stars in terms of being able to converse, take pics, get autographs, etc. is not something that someone from the TV/film world would necessarily be familiar or comfortable with.
"Get mad, then get over it." - Colin Powell