Well, I have seen dealers deliberately scratch items so they CAN have an excuse to sell them as demos or B stock.
I have purchased several keyboards that had 60-day return available, but only one I returned, and then bought something in it's place from them.
I think it's a valid way to go, if there is not one you can try any other way.
I'm sure none of us would purposely abuse such a practice. Would we now Diki?
DonM