Betsy gave me a GoPro for Christmas. You may have already noticed. She asked me to maybe use it for a little while before trying to attach it to the plane and losing it.
I did use it for non-aviation purposes and stuck it on a ski pole:

Having successfully used it without losing it I thought it was time to try something creative on the plane. However I really didn’t want to risk losing the camera and my wife’s goodwill so I used aluminum bar stock to construct a bracket on the tail of the airplane. Then I used the sticky mount that GoPro gives you but I also put two screws through it into the bracket.
Then, while in Arcata, in the rain, I went out to check on my plane. It was wet. Inside. Apparently I need to put silicon in a few places. I also decided to take it out and test the new camera / mount combination. I like it. The best part is that the camera was still there when I landed!