Dubba Tee Yo Pee also has an article on tipping Uber drivers. There is a jackwadd on there called DC Guy who posted something telling everyone not to tip Uber drivers. If you have a DISQUS account, you might go to the WTOP website, log on to the comment board (which DISQUS operates) and tell that guy what a jackwadd he is.
I don't like to just SAY what I would do but I can honestly say that unless the passenger had a BIG ONE UP on me they won't be doing that to me.
What really pissses me off is doing this to an unsuspecting older man that MAYBE had no guile and a dick wad took advantage of an older person trying to make his way through life, however he could, yet doing it honestly.