Leaving the products at the store is questionable..
I've seen it happen, where as the manager instills a strong trust between the customer and the store, to show a commitment to the customer that the store will be behind 100%..
Also, as this thread gets more exposure, I will bet there will be countless of posts showing someone's buddy going to a store, buying a product and then after going home, opening it to find something totally different from what they intended to buy..
Walmart actually caught a group of people buying car stereos, amps.. etc and then returning junk equipment, and resealing the box with shrink plastic.. after numerous complaints from customers buying the returned but sealed products, they finally caught on and inspected everything before being returned.
Im sure Microcenter can track what has been returned to them and what date..etc they could see if that particular motherboard was a returned item recently and any one with common sense could see "yea, a customer returned a XXXX motherboard on this date, and this particular model in our inventoried was returned xx times.."