Actually your reply reminded me of a motorhome owner on the pitch next to us in Switzerland who did the same thing. The trouble was that he only stayed for a week before returning home. This ment that it would have been cheaper for him to have declared his over 3500kg weight rather than than the false one (SF25 against SF40) plus the risk of a hefty fine if caught. He wasn’t a happy bunny when he found out!
My question was more to do with foreign police being able to tap into the DVLA to gain info, perhaps on a reciprocal basis.