Yep. I would hit things and there'd be the cracks.
What kind of cracks? If they're simply hairline cracks, that's caused by the fiberglass flexing and the gelcoat being more rigid and not flexing with the fiberglass. The only cracks that are covered by the warranty are those that are due to a defect in materials or workmanship.
I had a 5 X 2 inch piece of gel coat separate from the hull about two weeks ago. I didn't hit anything I knew of. I took it back in to the shop and they determined the problem was a manufacturing defect where an air bubble had been left between the fiberglass and gel coat. Warranty took care of it. No one I've shown it to since repair has been able to locate where the piece was missing so I'm pretty happy about the whole deal.