The original post is a word of warning regarding how important it is to make sure your rear brake is set up correctly and have nothing to do with the wheel other than the excessive heat from a poorly set-up rear caliper was the cause of the wheel failure. And yes, this probably would have happened with an alloy wheel as well, it just would have taken few extra sessions.
As background, I've got more than 35,000 miles and 11 years on a set of BSTs - almost all of it on the road and I've had no issues. They have however, improved the performance of my speed triple tremendously... worth every penny.
At the end of last season, I put a new set of BSTs on my Ducati track-bike and enjoyed increased performance as well. That said, I only put them on AFTER I had fixed all the issues of my rear caliper overheating. You see, I had replaced the master cylinders for my rear brake (Thumb brake + Foot brake). All appeared to be fine however, as noted in a previous post in this thread, the push-rod on the foot lever needed to be shorter (ground down a bit) so as not to put even the slightest pressure on the master cylinder (leave a 2 mm gap). Even a little bit of pressure was enough to fry the caliper after a 20-minute session on track. After I replaced the rear caliper an got back on track it happened again, which is when I finally figured it out.
The next month, to be sure, I ran the bike with the BST front and OEM rear wheel and compared the temperature of the rear caliper and disk to those of the front after a a couple of laps, then after the first session, when I confirmed the brake was good to go, I put the rear BST wheel on and had the best time all season. (Note: The front rotors and calipers will likely run a couple of degrees cooler just because they are exposed to more direct cooling up front.)
Clearly, the issue in the case featured in this thread was not the wheel, but improper set-up of the rear brake.
That said, it is important to note that excessive heat will degrade carbon fiber; that is why the BST wheels come with a warning to NOT use full coverage tire warmers (the ones that cover the entire wheel and not just the tire).
Also, I would have to agree that CF wheels are inappropriate for racing because they will get beat to hell if you are relying on a track-side vendor to mount new rubber, and more importantly they are not a good heat sink, which will make your rubber cool faster if you are sitting on the grid without warmers. You see, there is the issue of the tire's cooling faster than they would have on an alloy wheel since the CF wheel does not absorb heat from the tire like a metal wheel will (heat sink). Thus, your tires will cool down faster, which is a HUGE issue if you've had a red-flag event and are restarting on the grid after waiting 10 minutes for the track to be cleared and the race restarted.
I only put them on my Ducati after I stopped racing last year. So, if you are road and track riding, there is no issue. If you are racing, the issue is affording a spare set for rain tires, not caring about the wheels getting beaten up with all of the tire changes by people who don't really care or are not familiar with taking the care to mount tires properly, and having your tires cool quickly if you have to sit on the grid without warmers for an extended period.