Got a HD Surf Hero by GoPro less than a month ago and today it met its fate. Let the adhesive dry for 2 weeks, used the lanyard, the two parts of the mounting pad and the water STILL took it off. It now rests in the ocean near Pier Village NJ.... Nice.
Next time try the Surf Camera. Way easier to use and it will carry most waterproof cameras coming out today. The quality of these new compact waterproof cameras are way superior than the gopro too not to mention you can use it for your pocket camera on land as well. Check out the GE G3wp Surf Camera combo.
I have used both the surf mount and the regular mount and both have been on the boards for over 9 months with out problem. Maybe you got a bad batch. Maybe try to contact go pro and see if they will send you a new one.
I have one, got it for Chrtistmas. Never had an issue with the pad coming off though. Only problem I have had was the buckle that connects the camera to the mounting plate broke the 1st day I took it out. GoPro sent me 4 replacements pretty quick. No issues since then, that wheren't my fault(lost the thumbscrew while I was in the water, doing something dumb LOL).