I've rested my full body weight minus my left leg on all my carbon bikes whenever I'm sitting out a stoplight or waiting for a race to start, someone to finish their coffee, or whatever. It's comfortable and, like that post above, it was modeled by the pros. Now I can never really enjoy it in the same carefree manner again. Thanks.

As for the other part, I did break a carbon clincher rim running tubeless -- just hit a really huge pothole with a sharp edge on the far side, tire burped out its air, rim cracked. I think tubes make more sense for tires less than 700x28 or, better yet, tubular.