Check your local law. It is going to tell you that you have to stop.

What you do beyond that is up to you. Personally I find that cars get really confused when I act like them. When there is traffic at an intersection with a stop sign I give the right of way to the appropriate vehicle and go on my merry way when it's my turn. More often than not, they waive me through before them.

When there is no traffic, I hope a copy isn't feeling his oats nearby and roll through. ...and yes, I have been pulled over by a cop, he said "You know I can give you a ticket for running that sign, right?" My reply, "Yes." His response, "Hmmph. You need to stop. (under his breath... This summer is going to be different.) Stop next time."