There is a law that crypto platforms are forced to lock down a user's account if it has funds that came from a restricted persons lists. This means that if crypto was tainted from illegal activity and then directly transfered onto your account, you can be banned. You'll lose access to everything and it is literally illegal for the platform to tell you exactly why and/or release your funds.
This also means that it is quite easy to "taint" if you know what you're doing and use it to attack other users.