To speak or not to speak, that is the question

[Rottersod]

#1: Speak up as soon as you see it. Rules violations like that are every players responsibility to correct.

#2, Discuss with floor in private like you did. There's no point in asking the dealer or the table - you'll just get a bunch of angry responses about how "it's our money, we can play it any way we like" or "we were heads up so we can agree to this". It's a no win situation for you and the dealer. let the floor handle it. If he's on his game he'll come over, stop the game and let everyone know that this isn't to happen again and why it is collusion.