Sharp Impact
You've got me on that one, but.... we're probably at the same point with CF now that we were with aluminium pressurised fuselages 60 years ago with the Comet - we didn't know a lot about fatigue cracking back then and it took a couple of nasty accidents to open our eyes. Now we do routine NDT/NDI etc. to check for fatigue cracking and propogation - composite structure adheres to the same rules.
Inadvertant damage from birdstrikes etc - more difficult to quantify but I would speculate that a bird that was big enough to do visible damage to composite would also be big enough to do visible damage to a metal skinned aircraft. Likewise, if it didn't cause visible damage then the damage would probably be limited enough so that structural integrity wasn't compromised and the damage would be picked up at the next NDI.
All this is of huge interest to me as my next big project is an all composite biz jet!