On my '08 I've had one side come off (kerplunk!). I got a new one (and a spare) from Diamond Seaglaze and put it on according to the instructions. It started coming off again pretty soon after. Rather than wait for another kerplunk, I took it off and reattached it with 3M 5200. Seems to be holding so far, but I try to minimize the strain on it whenever I can.
The other side is still securely attached from the original installation.