I run a food truck (so should have put this under food & bev), but it really is like a retail experience... 
With the Square Register hardware, is there a setting so customers have to leave their cards in while they sign and tip/not tip? The way it is, it seems like they insert card, it's approved, they're prompted to remove card, then they walk over to get their food. I notice that my side of the Register says "Customer is Tipping," skip the tip for them, squiggle a signature and then help the next customer. It's dumb; they'd sign and tip more readily if the card had to stay in longer. 
Thank you.