I would be sorely tempted to tear that one up and get a littering ticket on top of it. Given cyclist's reputation for not stopping at stop signs, you'd think a cop would be happy that he stopped. I have actually thought that the roads would be safer if motorists had to put a foot down. At least they would stop. I have to laugh when people around here complain about cyclists not stopping because nobody stops for stop signs here, you'd get rear-ended.
California did actually require cyclists to put a foot down for a while. Kind of ridiculous given that most of the country calls a rolling stop a "california stop" for good reason. I really wonder if they enforce stop signs around here -- the cops don't stop for them, why should the rest of us?