Why do you have to fill in your tip amount?

Posted by Icy_Mixture1482@reddit | AskAnAmerican | View on Reddit | 140 comments

I see receipts in US restaurants seem to look like this: https://i.imgur.com/8vfQRHh.jpeg Why do you have to fill it in though? Do most people do that or just put down a pile of cash that includes the tip when they’re leaving?