That is exactly right, the ECAM will come up with a warning "Brakes Hot delay take off" if the brake temp is more than 300 degrees. We have brake fans on ours and this usually will take care of them within a normal turn around. Another trick engineers do is that they call an a/c unit and blow cool air on the brakes in high outside temp conditions, don't know however if this thermal shock is actually too good for the brakes.. .Cheers