Like the others said, they do not bend in the same manor that an aluminum does, but they can warp. Often times with cheaper ones they are warped from the get go right of the box. But over time from use and heat they can and do warp, especially at the tips. I have had more carbons go bad than I have aluminums if they are properly taken care of. Most of the bent aluminum arrows I see are from miss use, like being stepped on removed wrong or handled improperly. These same things can ruin a carbon as well, but they are a bit tougher in that respect.

I believe what happens with a carbon arrow is they start to break down from the inside, or even one can be smacked with another arrow or something and they can be damaged from the inside. You can't see it, but it's there, and when this happens it somehow pulls on the rest of fibers and causes the arrow to warp or bend. It also loses strength and spine.

I shot both carbons and aluminums for a while and put both on a spin tester periodically and actually had much fewer problems with my aluminum arrows.

Paul