It would be possible to derive who the million dollar purchasers of bored apes are. Crypto has fiat on-ramps that are mostly controlled these days. And if the crypto changed hands in the meantime then it would be clear where it originated.

Realistically, the buyers of bored apes are not really of interest to anyone and the NFTs probably won't be worth anything in the future.

When crypto is used to purchase things that actually matter then it will most likely be a trivial matter to identify whether the coins are "tainted".