In Sid Near Niagara’s posting he makes many helpful tips about archery. He also touches on the potential to have an arrow embed itself in your supporting arm, but states he has not seen this.
A very avid hunter friend of mine had a carbon fiber arrow that disintegrated into his arm. He spent 6 hrs in the operating room removing all the fiber shards and lost some mobility in his wrist. Fortunately this was not permanent and he has regained most all movement. He strongly regrets not having on an arm guard, and mentioned that he now is more conscious of the safety of his eyes as well.
When checking the integrity of a carbon fiber arrow, do the following:
1). Visually inspect the shaft of each arrow for cracks, splits, nicks, or fibers protruding.
2). Flex arrow between both hands, (envision the St. Louis Arch), and have the center of the arrow at least 3” above the ends of the arrows. If it does not snap, or make noise, it is a good sign of a “safe” arrow.
3). Lightly grasp one end of the arrow and tap against your leg, or a picnic table, etc… to listen for “loose” or odd sounds.
Lastly, as for knocks, keep an identical arrow at home for reference. If you need to re-glue your knocks, it is imperative that you do so at the appropriate location in reference to your fletchings or your shot could go wild.
Please use common sense and do not attempt such safety checks with broad heads or similar sharp points attached to the arrow. Ask your salesman if he has any additional tips for spotting a damaged arrow.