The concern is how it got stolen...
It is illegal to leave your car running while walking into a shop and coming back a minute later. Not sure about a good English translation, but you are urging someone to steal your car.
Depending on how his phone got stolen (it was a setup), he could be charged with something similar.
Are you sure? In which country? Because in Hungary we had a team of guys who regularly left bicycles out in the street (with GPS) and then waited for them to get stolen and then called the police with the GPS data. And it worked, the bike owner guys didn't get into trouble for leaving a "bait" out there. If someone steals it, they committed a crime and get caught by the police.
Correct, there's no restriction against a private citizen baiting you into committing a crime by simply leaving the means available. And it's still a crime, even if they intended you to take the bait.
If they try to talk you into it on the other hand...
The concern is how it got stolen... It is illegal to leave your car running while walking into a shop and coming back a minute later. Not sure about a good English translation, but you are urging someone to steal your car.
Depending on how his phone got stolen (it was a setup), he could be charged with something similar.