I had an older gentleman bring in a new X5 complaining that the lane departure warning was not working. I road test and it is working without fault. I bring it into the shop and run faults (for due diligence and the extra .5 labor time) and check for relevant faults. Nothing, send it. Next week same X5, same complaint. Again, road test and its working perfectly. My brain is trying to wrap itself around this and it hits me. I go ask the advisor to call the customer. With the customer on speaker I ask if the key fob he left with us is the one he uses or the spare. Its the spare. the customer had selected lane departure off on his key fob and not on the spare.