At our local crit series 2 weeks ago there was one turn that was causing blowouts left and right. I counted 3 after I showed up, and there were races before mine. I wasn't able to ask any of the riders what PSI they were running, but knowing racers it was probably pretty high. The day wasn't particularly hot, and the turn was on level ground, not banked at all. The only thing I can surmise is that the lateral force on the tire was pulling it up out of the bead, allowing the tube to explode.