Sorry, what I meant was that if the stitching in the seat fell apart then VW would still have to fix that, regardless of remap or not. However, if they do routinely scan the ECU for remaps every time the car goes in and then grass you up to the finance company, and you have to cough up the entire sum then and there, I don't think I'd be buying a VAG product again. Not that I can't see it from their side: Indeed, it makes sense, I just don't think that's a particularly nice thing to insert in financial agreements.
Gearboxes certainly shouldn't be covered if you've had a remap, there's even an argument to not cover suspension components as the extra shove could cause wear and tear on those...