Blades are (pretty much) expendable/consumable. At a dollar or two a pop, if a blade gets stressed or broken, you just put on a new one.
There are two schools of thought here: one is that the frame is rugged and indestructable, and that it should take a lot of punishment. That's the school of thought that this kickstarter is going down, and it looks really interesting (and like it should work just fine!)
The other school of thought is that the airframe, just like the props, is the "easy" part -- it should be lightweight and sacrificial. Break a cheap wooden boom? New cheap wooden boom and some wire ties == back up and flying in a few minutes. With this approach, all the less-easily replaceable bits, like the motors and electronics, are attached in such a way that they can break off and bounce without getting permanently damaged. That's the theory, anyhow!
Disclaimer: I'm still working on building my FIRST quad, so I'm not the voice of experience here.