One more doubt is that do you close the account if the coins came from a mixer as per the image posted by the user it says that and i have not heard any situation where a gambling account is closed because they used mixers.
I think using mixing service is not belongs to severe-risked indicators. If their system is able to detect about it and think the funding source is suspicious then they've the rights for asking KYC and earning source, Accounts getting suspend only if the core team detect that the risk to be related to illegal activities.
Mixer is something that actually used by a lot of criminals, it is actually a decent idea that nobody should be following where our money moves, but at the same time could be used by bad people as well, this is why I am a bit confused about it. I would prefer if nobody watched my money, or at least have the capability to watch my money, but at the same time I have money in an exchange that has all my information and my face with it as well.
Hence, I think it would be better if mixers were all banned from all places, from exchanges, from casinos, everything. However in that case you could simply open a blockchain.com account, get a new wallet, send your illegal money from your illegal account to mixer and get it to your new blockchain.com account that is clean and then send it anywhere you see fit, which would be still possible so I do not know what to think about them.