Surely, the only way that would happen is if the party that's requesting that information has reason to believe user x has broken the law. Advertising or even using the service doesn't mean you're using it illegally. Many users who are advertising don't use the service. Then, as has been discussed several times over the years, many users use services like these to retain their privacy. So, if a third party did suspect someone in particular of money laundering then they could potentially request theymos to release any information that could aid upon that. However, whether theymos complies is up to them, and probably done on a case by case basis.

If governments start cracking down, and deem services like this illegal, then advertisers would have to make the choice of whether they continue to advertise the service, since it would be technically illegal to do so. Until then, I can't see any reason why a party would request this information, unless like I suggested they can tie a particular user to a money laundering case.