I used 8 oz. polyester, PL Premium Construction adhesive ('orrible stuff to spread thin, I might add), and Rustoleum to cover mine. I've managed to drop an end on pavement while unloading, in addition to unintentionally letting it roll out of my grip and onto the paved driveway when putting it back into the garage. Nicked the bow and the gunwales up a bit.

The Rustoleum scuffed off in a very apparent manner. The PL was tough enough to handle the abrasion, as I didn't have any leaks afterwards. But the places where the paint was abraded off was very obvious. The damage was purely cosmetic, assuming I kept the sunlight/UV off the PL enough to keep it from being affected until I painted it.

Since I'm still fairly ignorant in kayak building, I'm guessing the Dacron/fiberglass method doesn't give an obvious "Hey, I've been damaged in this spot" message?