Lets say client A has 100,000 in his checking account and he writes you a check for $500.
If you come into the bank and ask to cash it, the bank is under no obligation to cash it for you.
The bank is obligated to cash the check drawn on that bank to the payee presenting the check during business hours. I got that idea from plenty of experience. The bank's only legitimate action is to pay it, or stamp it NSF to the payee presenting it and his DL. No fees can be charged, no thumbprints required, the payee can be wearing blue jeans, sporting a beard and be all sweaty. That's the rules. Banks can't sit on checks, modify the value of the instrument, or otherwise make demands.