Does the apple store check the serial number

[rgarjr]

When u return an item like a mighty mouse, do they bother to check the serial number on it?

I know they don't care checking for it at Best Buy.

 

[geoffreak]

If you didn't buy it there, you can't return it there. Applies regardless of what you buy.
Apple will (or should) replace your mouse if it has any faults that appeared after you bought it.