when i was younger, i remember having to get my bicycle licensed. the cops had a program where they came to your school and had a little safety course.
over the years, it kinda fell under the radar, but most states have laws about bicycle licenses on the books, they just aren't enforced.
it also helped if your bike was stolen.
in Huntington Beach, Ca, the year after the OP Pro riot on labor day, 1986, the cops used the normally un-enforced (by them) and completely ignored (by us) bike license law to stop anyone they chose, impound their bikes, and take people to jail for drunk in public.
at first, in order to get your bike back, you needed to show some kind of proof it was yours, at the very least a picture of you riding it.
after awhile, you could just wander through the impound and pick out any bike you wanted and say it was yours.
if you run down an elderly person on your bicycle, i don't think they're gonna react fast enough to see (and memorize) your license plate, anyway.