I was playing at my local B&M a couple of weeks ago and I was at the table for about 30 min. Throughout play, I noticed that 2 guys who sat next to each other always would enter the same pots, always raise the pots, but they never showed down any hands once the other people involved were knocked out, one of them would fold. It was obvious that they were buddies because they would always talk in between hands and during hands in which they were not involved.

I thought this was obvious collusion, but I didnt want to bring it for discussion with other players at the table with those two sitting right there.

My question is, how would I go about proving this? I could ask to see their hands if they ever made it showdown. But what would this prove? It would just prove to myself that I was right. Do I go to the floor and explain it to them? If I do this, i dont have any proof of collusion.