This is an odd shop, the more I re-read the initial post.
The 30-day return policy is certainly fairly unique, of all the shops I've visited over the years I don't think I've ever been to a shop that allow someone to ride a bike for 30-days and just bring it back, no questions asked. Heck, I ride with some guys that can put thousands of miles on a bike in 30-days. Which means the shop now has to sell a used a bike and deal with that, which can be difficult if it's a odd color or size.
The other issue is their inventory management. The shop I worked at was pretty meticulous with special orders for exactly this reason. We would pretty much triple confirm any special order, even more so with a bike. If the vendor shipped us the wrong size, color or model it would never even left the box. It wouldn't have been built and a customer certainly wouldn't have gotten a call to come in and pick it up.
"Your <insert random color> <insert random brand> has come in and is ready for pickup."
"Oh... I didn't order that."
"But it's your size and you can always bring it back if you regret it within a month."