I don't wear a helmet unless the weather looks like it's going to be atrocious. Just goggles and either a wool flat-hat in anything over 5degC and dry, or one of those Barber fleece trapper hats that were mentioned a couple of months back and which now seem to be sold out....
So what happens if I drive my car into Austria or Italy with just my normal headgear - assume I'd be stopped by the Feds?