When I was still working in downtown Chicago, there were food trucks that would park around the corner from my building. Every now and then I'd go to one of them for lunch even though it was pricy. One day their computer screen started asking for a tip; they got one but that was the last time I went.Why even ask for a tip up front if you are not providing any service outside the counter. I guess they figure a certain percentage will be sensitive people who will tip for nothing.