What is withdrawal, I've never heard of it

You made a huge profit from trading coins, earning a full 10 million, and you are happily thinking about quickly converting these virtual currencies into real Renminbi.
So you start looking for those who can help you exchange USDT for RMB. After some searching, you finally find one that seems quite reliable.
You both agree that you will transfer USDT to an exchange as collateral, and once the U dealer sends the money to your account, you will confirm the transaction, and the exchange will release the coins to the U dealer. This sounds pretty safe, right? But actually, there is a big problem here — you have no way to confirm whether the money the U dealer gives you is clean!
You might think about checking the number of days the funds have been settled, or asking the U dealer to promise to compensate if the card is frozen, or even finding an established coin dealer, surely that should be more reliable, right? But I'm sorry, none of these work! Because the issue of frozen cards is like a time bomb; when it explodes depends entirely on when the victim decides to report it.
The fundamental reason for frozen cards is simply that you don't know where the money the U dealer gives you comes from, whether it's clean or not. Even if there are no issues this time, a few months later, you could be traced and have your funds frozen due to some previous transaction being involved in a case. Not to mention that the U dealer's own bank card might be flagged by the bank's big data risk control due to frequent deposits and withdrawals, and cards that have transactions with the U dealer could also end up in trouble.
If the funds in a domestic bank card are entering and exiting too frequently, inconsistent with previous trading habits, or if there are quick in-and-out transactions without retention time, it could also trigger the bank's risk control and lead to a direct freeze on your account.
This matter is simple to explain — big data is just too powerful. Those who gamble online often use USDT for transactions, trading coins frequently at exchanges, which ends up associating their bank cards with those on anti-fraud blacklists, and they get monitored by big data. Moreover, most coin dealers’ bank cards are also high-risk accounts; if you deal with them too much, your bank card could also be tagged as fraudulent by big data. Making money is a good thing, but converting it to RMB requires caution!