Ed, as MMario says, they go back at least three decades. A more recent phenomenon (last 5-6 years, I'd say) is that products are listed in ads at prices which reflect the rebate, then in small print is listed the "up front" price and the rebate amount. I had just one Comp USA claim rejected, on the basis I'd neglected to send the UPC label. But, since I'd double stapled it directly to the rebate request form, I found it hard to believe they'd know about my request without also having the UPC. Just one phone call with a little bit of hollering got the rebate out of them.

As kat says, Office Max is pretty good, as is Best Buy. Both of these places print out the rebate request form(s) as well as as many extra receipts as are needed to send with the forms.