Not that it's a perfect source, but reddit lawyers used to describe the difficulty of proving entrapment by laying out two requirements: (1) you wouldn't have committed the crime if the instigator wasn't law enforcement, and (2) you only committed the crime because the instigator was law enforcement. One or the other is not enough. Like an 'if and only if' deal.

If you aren't aware that it's an LEO urging you on, I don't see why you should be able to argue impropriety. You made the decision as if it were real and would have real consequences.