I sometimes change the Drive Mode from T to S and back while riding, when I forget to preset it before starting to ride (but you have to have the throttle closed). I've been doing this since I got my new 2013 S10 in April of last year, without any problems. I now noticed that the User Manual says "WARNING - Do not change the D-mode while the vehicle is moving". I wonder if this is a safety warning or a damage warning. Anyone knows something about this?