Been to a few pubs where they have a tip option when you go to pay at the card machine and you can't pay until you've selected something. Just ends up making a long wait as people stand around trying to pay without realising they've got an extra step. People often cancel the payment by accident by pressing the wrong buttons too so adds more time when they need to set up the payment again (something I've done). Seen a load of bar staff just type in the amount and mash the button to skip the tip themselves then hand over the machine to the person paying.
Been to a few pubs where they have a tip option when you go to pay at the card machine and you can't pay until you've selected something. Just ends up making a long wait as people stand around trying to pay without realising they've got an extra step. People often cancel the payment by accident by pressing the wrong buttons too so adds more time when they need to set up the payment again (something I've done). Seen a load of bar staff just type in the amount and mash the button to skip the tip themselves then hand over the machine to the person paying.