I did specifically asked about the cardon check as it was a recall item and was informed initial recall check was free (which made sense) but as you say, future ones are an option which are paid for. I won't be paying for the initial check as it's their recall. I've never yet paid for any boxer recall checks. They've always been FOC as it's a manufacturer liability. As for future cardon checks, I won't bother. If it's ok now it ought to remain ok, and is a completely separate issue to the shaft spline corrosion issues. They're also going to carry out the drillling and plugging of the shaft drive casing which was also part of an earlier recall notice (GS bikes were done first as they were deemed more at risk).