I would have thought the actual driving to such an event is far more of a worry that actually riding in the snow and ice. So if I was throwing such an event, I’d be worried about not enough people turning up, so would postpone it rather and save the cost. Plus, these sorts of things get riders of all sorts of abilities. I doubt a manufacture would want to encourage riders to ride in conditions that are out of their skill level. Hardly health and safety gone mad, more thinking and looking out for people. You are still welcome to ride there on your own bike if you want. If they stopped you doing that, then I’d agree it would be health and safety gone mad.