A friend who has worked at a bank for ten years revealed to me effective methods to avoid having your bank card frozen:

1. After completing a withdrawal operation, that is, after someone transfers money to your bank card, do not immediately transfer or use the funds. Otherwise, it may trigger the bank's risk control mechanism and be deemed as fraudulent activity.

2. Try to avoid making transfers on non-working days, especially frequent transfers at night. Such operations are easily monitored by the bank's risk control system and may be regarded as online gambling activity.

3. When withdrawing money, prioritize fixed merchants and operate through a company account. It's best to fix the timing, such as the 15th of each month or the end of the month, so the bank will regard it as salary income.

4. If you frequently change merchants and involve large amounts of money, your account may be frozen for a long time. If it's a small amount, providing relevant evidence can unfreeze it within 2-3 working days; if no evidence is provided, it will take 7 working days.

5. After the transfer is completed, do not make small exploratory transfers, that is, after someone transfers money, do not transfer small amounts (less than 100 yuan) to WeChat or Alipay.

6. If the account is frozen, you need to bring your ID card and bank card to the bank counter to handle the unfreezing procedures and provide a clear explanation for funds from unknown sources.