The design of the spinners will encourage the spinner threads to tighten when in use, eg braking. IMHO the bigger issue is whether you can get the wheels off at the roadside, if they have not been regularly taken off during a service , routine maintenance etc. I had real problems with a 4/4 I purchased with full dealer service history, but old tyres, when I came to replace them so after buying the car, the tyre fitter who had extensive Morgan experience couldn't get the spinners off, they had been on so long and become almost seized on. Two hours and lots of wood etc later the wheels eventually came off. There was no way I would have gotten those wheels off on my own, let alone at the roadside.

For me the moral of the story is not so much an issue to secure the spinners and wheels on, but can you get them off, especially at the roadside in an emergency.

Having cleaned the paint off the contact areas, mine are better to remove, but still need heat on occasion. Obviously really not practical at the road side.

I for one, need a two ear one.

This has to be the best technique for spinner removal - gentle persuasion by SWMBO . If I ever get brave enough to ask that is 🤪

Could it be the spinners have been damaged by overtightening? This is definitely a situation that requires correction. No point in carrying a spare (assuming you do) if you can't use it by the roadside.