Blitzer nice greetings forbidden?

Hello! I passed by a mobile radar trap, which was rarely placed in a stupid way: in a residential area in a saushmalen road where the parking cars had an additional narrow spot, where nobody, who has his 5 senses together, would pass by more than at pace, and even more, despite the (not very dense) fog, could see the part from the next crossing. I was walking at a pace (Limit there is 30, but that was, as I said, illusory there, eng&Nebel&Zickzack wg. parked cars) and the boys in the speed camera car greeted nicely (to wave and smile). Then they flashed me smoothly! What did I do, please?