No way. CPUs are returned ONLY b/c of two reasons:
1. Original buyer was freaking clueless and couldn't figure out how to:
a. Seat the CPU (pins are now bent to heck)
b. Get the heatsink on...so the CPU is smashed and the pins bent to heck
c. So, after a+b they powered it on anyway, it overheated and the CPU fried
2. The buyer knew EXACTLY what they were doing. They got the CPU, overclocked the crap out of it, the CPU didn't hit XXX.XXX GHz before it fried...and they returned it.
IMO, for every 1 person who successfully buys a refurb CPU, there are 99 people who discover this was a really bad time to be a cheap person and buy a refurb CPU.