Have you ever taken a tire off the rim? or seen it? Its not just a smooth prcess. Stretching the tire out time and time again to mount and dismount it wears on the tire.The sides and the seal will get weaker. also scraping around the rim is unessasary risk of damaging the wheel.
anyway may not be drastic but I would not want to dismount and mount my tires eve 6k miles or so.

+1 Mounting and dismounting a low-profile tire raises the potential for rim and bead damage.

I have 70,000 km on my E53 X5, I have never rotated the tires, and the tread wear is very even. Had runflats on the Z4, and the wear in the first three years was very even as well. The only benefit I have associated with rotating tires is balancing out the wear. So, I can't see the point with these vehicles.

+2...Buschy & JCL nailed it, imo.

As for SpeedR doing the rotation thing: whatever you like;
if it was a rec'd procedure for Xs, which it isn't, you can
bet the Stlrs would be humping the process, esp. post-warranty.

I save the "rotation" for the grocery getters...

I just balance the tires every 7k or so and thats it.