I wonder if the couple could make a profit on this mishap by suing anyone who accuses them of stealing phones (i.e. on social media) after visiting their house.
Hence the after I deliberately emphasized. If they had already visited the house and not found their phone (especially if the police were there) then subsequent claims of theft against the couple would be much closer to libel.
So you're saying the couple would have to allow a stranger to go through all their person belongings until they were satisfied the phone wasn't there and then sue?