LOL at this. Not only did you take the time to make this post, but you also had to notate on the screenshot. When I see stuff like this, the first things that come to my mind are not tax evasion or "whitening black money." If you are trying to evade taxes you probably don't want to be raking in thousands of dollars in worldwide wire transfers. I'm sure there are a multitude of reasons for this though. As another poster said, it might draw scrutiny from the sending bank. They could probably care less what you write in the message field, but its less of a headache for them when people have thousands of dollars sitting in limbo and they are pissed at Bitmain. I'm sure this scenario has played out many times for them. If you are concerned about funny money shell games I hope you don't use Apple or Google products, because those are 2 companies of many that shuffle money between tax havens like a casino blackjack dealer.
i am not a lawyer but maybe lawyer can see something wrong here, maybe all it is ok ,i just wonder. So if bank dont allow it means there something suspicious.something not correct.