The willingness of the US to swap prisoners incentivizes the Russian government to jail American visitors on trumped-up charges.

If I was in charge of US policy, I'd make everyone who wants to board a plane to Russia watch a 10-minute testimonial from one of those prisoners saying how bogus the Russian police / court system is, how not-fun the Russian prison system is, and how it bothers their conscience that the US government had to buy their freedom by letting a hardened war criminal go free.

Then if they decide not to go, the airline has to refund their ticket.