While the producers are blaming the actors, director Michael Bay is blaming the Marketing Department.
I do agree that that US poster is terrible (dunno what the international one looked like, can't remember it), I basically saw nothing about it on TV and half the complaints here are about the trailer revealing too much so he probably does have a fair point, though wisely he doesn't lay all of the blame on them.
[edit]Actually, this defamer.com article is interesting, basically Bay has ended up taking the blame.[/edit]