Marketplace Parking

I know this has been discussed ad nauseum over the years but the news that the Marketplace is to be made more 'pedestrian friendly' has puzzled me.

I obviously don't understand road signs!  At the entrance to the Marketplace is a sign with a motorbike above a car inside a red circle as pictured.  This sign means "No Motor Vehicles".  Surely every car & motorbike in the marketplace that is not delivering is breaking the law?

Why do we need endless council meetings regarding what to do about the parking problems.  The sign makes it quite clear & it is a simple matter for the police to enforce it.  Park a patrol car at the entrance to the Marketplace & issue everyone who drives in, past the sign, a fixed penalty ticket.  People wouldn't drive the wrong way down a one-way street & this sign means exactly the same thing.  Why is everyone in Wisbech totaqlly blind to this?

Maybe someone could either tell me here why I'm wrong or call the police to sort it out :)