Had a rather bad experience a week ago when, unbeknownst to me, a small rag fell out of my back jersey pocket and fell on my chain at a stop light. When I took off, the rag got sucked into the RD and snapped it off. The pulley housing came around and hit the seat stay. See it here:
http://www.bikeforums.net/showthread.php?t=593808
Anyway, when I asked about assessing the damage, one of the posters suggested the "tap test." The idea behind it is sound (no pun intended.) Tapping a good carbon tube will yield a certain sound. If it is cracked, the sound will be "dead." Short of an Xray, it seems like a petty good test.
What do you think?
BTW, the mfgr has a "no-fault" replacement policy, but since this "failure" is not "manufacturing defect" related, it will not be a "no charge" replacement. There will be a discount off list. I figure I'll probably just ride the crap out of it and if it fails (and I survive) I'll consider the replacement then.