I was with my best friend when an almost identical thing happened. You know why he didn't know? He just paid it via mail, didn't go to court. Because if you go to court, even if you just plead guilty and pay it...if they're going to suspend your license, they make you surrender them.

EDIT: And, NO, cops don't do this on purpose. It's YOUR responsibility to know if you're driving on a suspended license or not, they're just doing a job.