[pokerponcho]

Poker is a communal game. If the situation at my table arose I'd craftly mention that "Players should really protect their cards in a place like this." and I'd 'incidentally' point at the one exposing his cards to his opponents with my index finger. The table should co-op with ethics to prevent this sort of thing from happening. And that sort of co-op should be the extent of collusion in poker.

It is a form of collusion to peak at another's cards. One player is collaborating his opponents information with his own, despite the fact that the "sucker" is unaware. You should not be put into a postion where you feel you have to outplay a team, even if it is an interesting problem. The "sucker" is teamed with the cheater. If the "sucker" doesn't take the hint, then I'd tell him flat out that the X seat is peaking.

Just because one is in a position to be "in on it" doesn't make it right. And it certainly is not in the best interest of the game. This is a place where the pigs get slaughtered. I wager that almost as often as not the play would backfire. Basically, if I was forced in the situation (like with a gun to my head), I'd view it as an unreliable tell. It is in fact a tell of a tell. Player B reads A like a book and as player C, I have certain reads on player B which may or may not translate into reads on player A. Sometimes these reads I get on player A will be false reads and I will lose money. This is especially true if I am greedy and try to adapt too much to the situation.

If the colluders were on my left I'd play much tighter because I feel that player B will play more aggressively towards A, since he is able to make the perfect play against him.

B is likely a greedy pig. That's probably why you spotted him in the first place. So he will try to adjust his play too much to player A, even if he is an expert. He will try to isolate against the weak player too many times. Re-aligning your strategy towards him (and consequently the team) should not be too tough. Be more inclined to re-raise, but do not get out of hand, unless you want to be a greed pig that gets slaughtered also. Taking down 1, 2 or 3 pots by isolating yourself against the cheater with decent holdings should show a nice profit in a game like that. However, I would avoid raising wars and I would not try to "out-bluff" him because this tell is far too unreliable.