It's not, it's just audited. If you go to the bank and give them 10,000 dollars they don't lock you up. They just have one of their people do some research and ask you for some paperwork.
Now, the police seizing money is different, but the police are the police. They can do almost anything they want, and you have next to zero recourse. Of course, they're going to abuse this and steal your money.