Tena,

I have two sets of Oakley shades. On the Montefrio's the stems (bows) are fixed in place with a typical hinge assembly. However, the Half Jacket's bow's are indeed able to pop off of the frame, as you say keeping them safe. This has absolutely kept my Half Jackets safe on multiple occasions. I have opened the bag that they are in to find five pieces (Frame, lenses, and bows). However, I would never claim "unbreakable". The lenses are quite destructible, and you can most definitely break the bows if you really wanted to.