30-40mph doesn't seem fast enought o make it fly out, but that same seat in my X2 would try to lift off at hiway speeds.
Put a strip of velcro along the front edge, works good (when you get a new seat).
'06 X2 MCX
"I understand why some people may not want to do this the way I have recommended but I can't understand the death grip some people have on a toilet plunger with a hose fitting." -JimN