I work for Geek Squad, and at my particular store, the people are actually pretty intelligent.
At my store, we don't take computers in for repair until we've inspected it and ensured that we've found the issue, so that we can continue on with the needed repair(s). In a case such as a loose IDE, or SATA cable, we wouldn't charge anything at all.
A PSU failure? Perhaps he should have tried to turn it on... I don't know how that kid got the job at Geek Squad, and quite honestly, thats embarrassing.