Uhhh, you are aware we're talking Washington, DC, here aren't you?.............
I played in the Montgomery Street station in SF’s Muni system back in 1996-1998 with a string quartet. We routinely made about $40-50 bucks each for an hour after we split it 4 ways. DC is just not used to street musicians.
Also, a string quartet gets more notice, I think.
Finally, I should note that we also tried an experiment. When we dressed shabbily, we would make less money. When we dressed semi-nicely, like we were doing it for fun, not because we desparately needed the money, we made a lot more money.
Getting to work late is still not a good thing if you want your career to advance. It's (unfortunately) easy to avoid getting fired by the Federal government, but if you want to advance your career, you do have to work pretty hard. Thus, most people try pretty hard to make it on time.