I visited the Honda dealership in Arlington, MA. They tolerated me wandering around the shop for an hour wearing the helmet that I ended up buying. I decided that if anyone asked me what I was doing, I'd tell them that I was practicing to go out for the part of Darth Vader in a local play. No one said a word, probably because I was about to hand them $300.
I don't think that anyone would let you leave with one. Nor would they probably allow returns (after all, would you buy a helmet that someone took out of the shop and then returned?) The hour wearing session wasn't perfect, but it did give me an idea if there was anything seriously wrong with the helmet's fit.
I didn't worry about health issues, although I guess that it is possible to pick something up by donning a demo helmet.
Chris
