[bav]

Either OP's story is a bit garbled, or it isn't collusion. A cheating team doesn't signal "I'm about to fold" to the player behind; that's what a poor player who is accidentally or uncaringly telecasting his intentions does. A cheating team signals "I need you to bet after I check" to the player behind, or "I need you to raise behind me" or signals to the player in front "I want to bet, you should check raise". Those are useful signals.