When my gf was looking for a laptop for college, her dad was going to buy it for her, naturally came to me and then asked me if the geek squad stuff was worth it. So to prove my point, I went up to an associate and asked him how he removes viruses and he told me he just wipes the system clean because all infections are irreversable.
I then asked if he tried any data recovery techniques before wiping the system and he told me that is what the waivers are for. Easiest $200 I've ever saved someone.