I have no problem w/tipping either. I'll reward well for good service. We often get carry-outs from local restaurants (not fast food place) when we're actually in the field (not much yet this fall!) & I usually tip the lady taking the order & having my food ready when it's picked up. Let me assure you, it's well acknowledged in future orders also. When service is noticably bad or wrong, my tip will show that also.

If you've never had a family member working as a waitress/bartender, then you probably would not even believe their base pay. I understand which jobs rely on tips and which will get the customer preferrential treatment. Pizza delivery kids are also often abused by non-tippers. Ask them what their base pay is & who is paying for their car & expenses. 

I didn't think UPS folks could accept gratuities however?

As for the couple in the news article....I support their decision 100% to not include a tip & I almost can't believe the bartender called the cops. Very poor decision on his part. I truly hope he loses his job over that incident. That's my thought & it means nothing to anyone but me.