Boy, I can Imagine the noise and increased power consumption that would result from something like this. Also, I seriously doubt that and hard drive could perform as quickly as a modern solid state chip. I can picture myself using most/all of my battery defragging the stupid thing. Boy, I sure do hope that Seagate's defragger is at least a little better than the one that come built into XP.
Also, this "Rescue and Replace" plan sounds very much like a warranty. However, since digital-oriented corporations are becoming more and more unfriendly to the customer, it is perhaps inevitable that this be a subscription-based plan. Odds are, it's probably meant to give Seagate as many excuses to not honor this plan as they could fit into one agreement.