Do you tip when ordering takeout?

Say you're ordering food online for pickup.  
The last page of online ordering has an "add tip" option, with "no tip", 5%, 10%, 15% and "custom tip".
How much would you tip someone for literally just handing you your food? From my understanding, there is no obligation to tip when ordering takeout, but I know not tipping is frowned upon. I'm leaning toward 10%.
What do you think?