A question of online tipping etiquette
So hopefully this is the right place to ask this - today, I ordered a pizza for delivery through an online system. The payment portion offers the option of adding a tip to the final total. In the past, I have generally chosen this option, both because of the convenience and sometimes I just don't have cash.
Today, as I walked out to pick up the pizza, the driver made an offhand comment about a tip. I was a little confused, given that I thought I already took care of the tip on the original bill.
My question is: Do these online tips go to the drivers? I certainly don't want to stiff the drivers, but I also don't want to end up tipping multiple times. I'm not sure if I'm just misunderstanding the system - any advice would be quite appreciated.