NO Parking

I think most of us parked his car in a no parking zone at least once in his life .. I do it sometimes when I have no option other than that but its not the case in the following picture because those guys had plenty of empty parking space and they still park in the no parking zone.

I dont know what we need to do to let those idiots know that they parked in the wrong place .. maybe a big "NO Barking" sign with a big B