Radar traps

Dear community, I don’t drive a car very often, but when I drive it it’s 1,000 km long distance (between AT and Lux, respectively Lux and AT)… Unfortunately, sometimes a “malheur” happens to me, so that I tap into a radar trap (you can recognize it by lightning). My car has lux. license plates and neither Luxembourg and D nor Lux. and AT there is a legal agreement, m.W. after. This has the “advantage” for me of course, that I don’t have to pay any penalties, since I don’t have any mail from the deuts But now I have a question. Let’s assume that I am stopped by the German or Austrian police, does this mean that I have to pay all the offences on the spot, or how should I understand that? When do the bus fees expire? If I change the license plates, should I theoretically be out of trouble or? Just so that you don’t misunderstand me, I’m not a danger to the general public. However, it happens more often that I drive 140 – 150 km/h instead of 130 (predominantly on the road at night).