Sadly, I suspect that many other pilots in the civilian world would agree with me when I say that I would fear for my licence if I deliberately broke the 500 feet rule. I know that you are allowed to break the rules if essential for safety's sake, but you do then need to report this in writing to the CAA, and I, for one, would suspect that the CAA would claim that if that became necessary then I shouldn't have been flying in the first place. There's no hiding from CAA/radar traces when you're in London airspace. Poor judgement = no licence. QED
I suspect that you are right in saying many would fear it but I don't agree the CAA would wade into you in cases of a genuine degrading of wx. It would send a very bad message.