You're kidding? Can't they just reprogram a new fob for you? When my daughter lost the keys to our sigX loaner , they charged us around $60 for them to reprogram another. Couldn't they do the same for you and just send it in the mail or have you stop by and pick it up if they are worried about security? That seems lot more sensible than having to schedule a service apointment and pulling the seats apart.
The problem is that the old fob "hiding" in the car makes it impossible to lock the X (or S). Folks have gotten their S's stolen this way (leaving it in the car and parking it outside). Or at least that's my interpretation...