Once you come out of a mixer or coinjoin, you could send your coins 2 or 3 more times to other addresses, within some time. Maybe something like this will help. I can't help but think that if mixers and coinjoin were such a problem, that you would see accounts frozen and flags all over the place and we are not seeing that. I know accounts do get suspended, but is it really happening at such a high level? Does not appear to be the case. Coinjoin has a lot of daily traffic.