Sounds like it's not common then, which is reassuring.
I arrived at altitude because, once committed to climbing, I had little good alternative. Not IMC rated, but able to hold the wings level and correct airspeed etc because I had once practised with a colleague.
I had got into trouble in the first place by flying under and dodging rain to get home. This was the really big learning experience for me, and I will in future be the first to turn around. I had not appreciated just how quickly a cloud base can jump down on you. Once the perspective of the horizon had been lost I didnt have a safe way to turn round. Maybe descending would have given me back some visibility, but I had to make a judgement call, so I went up. I had anticipated that I would find clear air much lower, and was getting more worried all the way up beyond 5000.
Scottish ATC were great, allocating me a dedicated controller until I got down. I fortunately did find a hole and descended through it. Eventually made it to a retired military airfield. I learned more on that trip than I have ever done, and I appreciate my good fortune in being able to talk about it.
Legality probably not an issue as I was doing my best to get out of trouble. Judgement certainly an acknowledged problem as it got me into the trouble in the first place. Flying is a complex business, and some messages dont get properly assimilated until suddenly they become very relevant. This was my learning opportunity and I got away with it.