What I'm going to relay to you is a personal experience but I have later learned that this is a practice used by another bank chain.
It all started when I was, in a sense , laid off from my job for two months. I  was finally called back last month and things are starting to get better. While I was laid off the account, that my check was automatically deposited in, was closed. So I wasn't for sure where my check was going to go. I tried to get it into my wife's account but there wasn't enough time to arrange it so I finally had to get a hard copy check. This all took place on the 10th of this month. I had written my landlord the rent check on the 1st and asked him to hold it till Monday the 13th so that I could be assured the money was in there. Seems he forgot to tell his wife that and she deposited the check on the 10th. I told him the check would bounce so we made arrangements to get him the money after it did. We knew we had enough money to cover the charges and checks that were outstanding and when the check didn't clear we'd have the money to cover that charge also.
The check was presented to the bank on Monday the 13th, however with only $50.00 in the account they took it upon themselves to honor the check. We are now over $700.00 in the red to the bank. Not only that but they took the big check out first draining the account. Then they were able to honor the other charges that came in , but charge us a fee for each one of those also.
Now my wife's check that the bank received on Friday was gone before it got there and since my wife's check wasn't big enough to cover the entire overage they will charge her so much a day till it's taken care of. This is not right. this is a scheme to once again make money off of others misfortunes. There was no prior agreement with them, they had no business covering the check.
I'm in the process of writing my State Atty General, Congressman, Senators,etc, etc
and I would encourage you to do the same.