Actually, Best Buy lets you more or less do this with their 30 day return policy.

The other examples were just to point out that people generally check things out before buying. Obviously, different items are checked out to different extents. If I was a new customer of yours and wanted to buy a high end bike I fully understand not wanting to let me off the lot. Lots of bikes get stolen that way. However, if I'm a frequent customer and you wouldn't let me ride something (be it a demo, customer bike, or similar lower priced model or maybe same bike but with my wheels) then I probably wouldn't be a customer for long.

It's the attitude in this thread that's annoying. Maybe I won't learn anything useful from a test ride but it's my prerogative as a the one buying to make that decision or shop elsewhere if I can't. If I have to order the bike because it's not in the store then I fully understand I won't be test riding because most shops can't afford to bring in a bike that they generally don't stock and get stuck with it. However, I'm pretty sure my LBS would find a way to get me some saddle time on something similar before they order so I can feel confident that it's the right bike. Owning several Cannondales I want my next bike to be something different. I expect to ride it or similar model before I buy it.

I admit you are a better and more experienced rider than me and you and I will have a different approach to buying a bike. Why would you think that someone with less experience than you should approach a bike purchase in the same way?