Sorry, but I'm not sure how you came to that conclusion. A buyer and a tester are one and the same thing. An LBS cannot conclude that someone isn't going to buy just because he/she didn't bring pedals and shoes. A test ride also increases the probability of a sale because it places pressure on most people to make a decision. This is why car dealers always keep pushing the customers to test drive. It's a business.

Now if we're talking about test riding a 6K bike or a Ferrari, there can be certain precautions in place for that. But the type of the bike itself - mountain, road, tri - does not matter.