Is it unreasonable to think that if I brought in a laptop with a power problem, CompUSA's folks could try out a new power cable and/or battery before accepting my laptop and keeping it for three days? They seem to think so. I'd still pay the full service price, of course, which by the way is $139.95.
I've observed that I could probably wander into CompUSA, unplug a demo model, and check my own machine. Or, if it really is a battery or cable issue, I could probably buy both of those for cheaper and try it myself and be fixed faster. The issue for me is time. (Every day they have the laptop is another day I risk having them "fix" the fact that this machine has only Linux installed.)
Fortunately, these kind folks will take a look at my machine for me while I wait. I suspect now it might be more serious (may have even wiped out the power supply or something), but these folks will be getting my business (and my eternal word-of-mouth advertising).
Hint: give your customers what they want.