I use the cart for my Hobie Compass, but I'm not going far, or over any kind of rough terrain. I also don't carry a ton of gear, and that weight is pretty much centered over the cart anyway. I've looked at the cart scuppers, and they're reinforced. There's also so much flotation inside that if there was a crack, the boat wouldn't sink. Seems like Hobie figured a few things out that others haven't yet.
That all said, I can't think of a better cart for non scupper use than a C-Tug. They just work.