[cedws]

Not quite that simple, that’s vulnerable to an Eve-Alice-Eve attack. If $1B in BTC moves around in short succession the TXs can be linked easily. You need a mixer that splits up the amount to be paid out, and even then it needs to be done piecemeal.

[dzhiurgis]

Do all outputs from exchange are automatically trusted? Seems like any should be tainted forever. Or is it impossible to tell whats from mixer?

[cedws]

There are companies (Chainalysis) that track blockchains and ‘grade’ wallets according to who they’ve transacted with. If enough of a wallet’s funds are from a mixer it may be scored a grade lower than the exchange’s KYC rules allow to do business with.