The law regarding minimum speeds is a bit tricky in some states. I don't think maryland has one posted (nj doesn't either), but at least in NJ it is at the discretion of the po po to decide if speed (whether high or low) is dangerous. On a road where people regularly travel 75 I wouldn't put myself in a situation with a speed differential of 25 mph when the driver behind me has no way of knowing that differential until he/she runs up behind me.
I don't think he was nuts for driving 50, per se, but disregarding the police and trying to play coy about the reasons a lot of drivers hate us is only going to spread animosity.
