Crime, unfortunately.

Money laundering is done to “clean” illegal profit (hence the name). Say your business sells a bit of a meth precursor to a high school chemistry teacher for more than it would legally. You need a way to explain the extra money, and a way to explain where than precursor went.

Things that this won’t protect: sex work, drug dealing, hawking stolen goods. Things this will protect: owning a building where you were unaware every tenant was a sex worker, running logistics company that some bad apples on the exact same routes always carried packages of cocaine, or selling artifacts smuggled out of foreign countries.