Wait, your now categorizing the discussion (conspiring) as falling under the rules of collusion. I am pointing out that the act must be completed in order for it to be collusion. Since the act is acquiring the QB, all teams have the same opportunity participate.
Based on your scenario, both the 6-4 team should have been guilty of collusion even if the 3-7 team never went through with the trade? The trade had to go through to complete the act of collusion.
The essence of collusion is conspiracy between multiple parties. We use it in fantasy football to distinguish between unilateral or independent acts. It is generally accepted that if someone does something on their own (poor trades, bad drafting) you must allow them to manage their team. However, we must draw a line somewhere and opt to do it when teams cooperate to do something sneaky or wrong.
I am not categorizing simple discussion as collusion. I said that if teams conspire to discuss something specifically to mislead or persuade someone to do the wrong thing and they then follow through with that discussion, it is collusive. In this example, the "act" is discussion.
In your example, if two teams discuss a collusive trade, but never complete it, I agree there is no act and no collusion.