Compatibility with carbon mtbs

Hello guys! I just bought 2 neo 2ts to use with carbon fiber xc race hardtails. I have a few questions...

I saw that the endcaps are fixed in the trainer, they do not rotate. I worry that the mountain bike, even with the fork locked out, pivots more up and down than a road bike and that this could cause the endcaps to "eat" into the frame, damaging the dropouts. Do I worry to much? Anyone using their neo 2ts with carbon fiber mtbs? 

Thanks!