I thought about a cable lock but ill just throw a small lock on the box to (like i said) keep out the honest thieves, i'm not going to too much fuss to protect a $50 unit. Plus if someone wanted it that bad they could just tear or cut into the membrane. I like the ram ball mount to make a easy removal but i can also just keep a hex key handy and remove a bolt out of the tech mount. This will get a real good tr during my iron butt trip to South Dakota in June, ill give it some dry runs in the mean time
Like I said before, I rely heavily on my GPS for my living, so I don't want it stolen. It never coms off my bike unless I'm doing a firmware update, or if the wife and I take a trip in her car and I want a GPS that doesn't suck.
The ball mount isn't for easy removal, just a mount I already had from a previous project.
Not saying your way is wrong, just sharing what I did for the masses :).
I do highly recommend a silica packet inside tho...