A lot of it depends on how you approach the purchase. Dealers are pretty adept and discerning the tire kicker from the real buyer. I've never been refused a test ride regardless of brand or model. I narrow down my choice and then talk price. When a price is agreed upon I made the purchase conditional on the test ride and if for any reason I don't like it, no obligation on my part.
We should remember that lots of buyers want zero mile bikes because you never know what some one did when they got around the corner with that new bike you are now buying. Dealers would have to disclose if someone dumped it even if they fixed it and have you priced the cost of plastics? Newbie dumps it and the dealer is out a couple grand just to make it right and no sale. Insurance, that costs a lot of money if you're going to let some 19 year old hop on a Gixxer and head out for a spin. If you bought a new bike and had to sell for some reason and that hotshot shows up with a laughing buddy, would you let them take it out for a ride without some reasonable assurance they are there to buy?
When a dealer expressed hesitancy, this worked for me: here is my check for the purchase price subject to a test ride that meets "my" satisfaction and regardless of the reason, I can decide not to buy if I don't like it". Works 100% of the time so far.
It can be tough if you want to compare bikes but this is BARF, bet there is someone willing to if nothing else, take you for a spin on their bike to see how it feels and maybe even let you do the front end rider thing. If not, you can rent almost any bike if you look around enough.
Last thing on the damages part. No dealer would want to let someone ride a mid priced bike that if dumped will cost more than half the new price to fix up. Kiddies wanting to ride hot bikes can and will do amazing damage within seconds, sone before they even get into first gear, right in the lot.
