I don't think it's something you have to worry about so much? I'm pretty sure I've read somewhere that the strength of the square cab is vastly improved over the previous models (mine). Going over in a round cab is not something that you want to do.
Knowing what they are capable of I very much doubt I will ever push it anywhere near it's limit, but I would be much happier knowing I had something over my head should the worst happen! I'll have a closer look at some of the Breslau videos on Youtube. That could offer up some info perhaps. The forestry mogs had a good cage on them but it takes up bed space and I don't want that.