> you have to take affirmative action _not_ to tip, and people in line around you can see, so the social pressure is enormous. A foodtruck I watch on twitch ha

> you have to take affirmative action _not_ to tip, and people in line around you can see, so the social pressure is enormous. A foodtruck I watch on twitch has everyone choose an option. No tip, some pre-set amounts, or custom. So no social pressure there, as no one else will know. They are using the square register.