His post was a good read but I didn't see anything which demonstrated any risk. The only risk related comment he made was:

"That is what can disturb sediment that wasn't otherwise hurting anything, IMO."

However he earlier stated such a risk was:

"My lack of support for changing the fluid is not because "BMW said" but rather because I see little benefit to changing it, and a small but real risk. The risk of damage is slight, but it exists."

I do see his point of:

"At the same time, I think that the transmission is likely to fail from non-fluid related causes prior to the fluid degrading to the point that it causes a transmission failure itself."

But I'd rather minimize the likelyhood of such failure by ensuring the fluid is in good condition.