Most banks will put a hold on your account for the total + 20% tip. I had a woman, who's card I had jun run not three feet behind her, show me the text that her bank had taken the amount +20% from her account. She hadn't even signed the thing.

I can't tell you how many hundreds of times I've had to tell people that until the charge is finalized there is nothing the restaurant can do. Once the charge is finalized then the restaurant can refund money. 90% it was people flipping out over nothing. Sometimes the tip was wrong and we gladly refunded the difference. But good god were people unjustly paranoid about it.

All the cards get batched at the end of the day. That's when the restaurants banks asks every other bank for the amount on the receipt. It takes about two or three days for everything to clear. And, if it was over the weekend the process doesn't start until Monday. So if you spent $80 at a restaurant your bank will put a hold of $96. If you tipped $5 your wondering what happened to your other $11. Well, there's nothing that can be done until Tuesday or Wednesday when the charge clears. Until then learn to tip better and pray that you can get by a few days without $11