Hi Rob - this one's for you... ;-) Carbon frame meets hammer...

Carbon is great at taking the impacts, and cosmetically looking OK. But look inside, you have no idea what the condition is until.....

If a Kevlar layer was inserted, then catastrophic failure would be averted, but the kevlar does nothing to aid in the structural properties of a bike frame. That's why it isn't there in the first place.

That being said, if I was building a carbon trail bike there would be a kevlar patch at the bottom of the D/T to protect the carbon from abrasions and stone impacts.

I like the one where they have it in the vice:

http://youtu.be/SDVpRSNtcPQ

Always one funny bugger lurking around...