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.