I'm wondering how entrapment works with Bitcoin.
For example where law-enforcement offers to buy illegal goods or services from somebody.

What you usually see in the media is that once somebody names a price or accept payment, you get arrested. How does that work for transactions where the payment doesn't go to you directly? For example, a person makes the exchange once the police-officer donates money to a charity or a Bitcoin address that you don't control.

Wouldn't it also make entrapment much more expensive if criminals request bitcions to be put into escrow transactions before they make the exchange or even bring out the goods. If the suspects are somehow forced to hand over the private keys they will be incriminating themselves.

How could this be solved by U.S. law?