It's why I'm going to try to heat it before I give up.
I might also go get a snapon hex bit, extension, and breaker bar. I bet it wont flex like my craftsman does =D
So please clear this up for me. You're worried about breaking a bolt off while loosening it, so your options are to try once more or have no protection?
I hate to say this, and I'll never tell the story, but I have first hand experience on how well they Canyon cages protect the bike.
Obviously I am not an experienced mechanic, but I have been around the block once or twice. And I can say that a bolt breaking on removal is not as common as on installation. I'm sure it is possible, but I would assume that it would be on a lesser grade of a bolt. Being an engine mounting bolt, I would say that it is a hardened bolt, designed for this stress that it will endure and that it isn't your standard butter bolt from the local hardware store.
When I put my cages on, by myself, I didn't measure the torque of its tightness. I had read the same stuff on these forums about the nightmare installs, and knew that I needed to be smarter than the object I was working with. With using a decent quality tool(s) I put all my effort into making the bolt turn the way it should. Meaning that I kept proper alignment on everything, while I was putting everything I had into moving that breaker bar in the intended motion. And with a "snap", the bolt was turning.
I cleaned the threads on both surfaces and reapplied blue loctite on instalation.
A day later, I unwillingly tested the usefulness of the CC. So to answer my own question from my opening of this post, I would definitely go with the try again option.