In the US millions are stolen per year. Nobody knows the exact number because I suspect many may not even realize they've been stolen from and simply think they lost their phone somewhere. Thieves tend to target touristy areas where this is even more likely.

It's also going to make the targets even less likely to report the crime to police as well. 'Hi, I don't live in this country and I think my phone might have been stolen somewhere at some point in time over the past several hours, maybe.' is not even going to be investigated by the police, even if somebody does decide to file a report.

Come to think of it, this may all be yet another reason why thieves don't tend to abuse personal information. That sort of stuff is going to get reported and can be viably investigated by the police.