Has anyone done a Transmission filter and fluid change and caused more issues?

[Johnny_5]

I just took my car in yesterday to do a fluid and filter (x5 4.4i 200k) and the owner once opened opt not to replace the fluid as he has seen to many cars / suv's have total failure a month or two later down the road. Stated the worst is flushing the entire system? So he just swapped out the filter and threw in the old oil and topped it off. Ive read somewhere if you keep up with the fluid changes its ok to change out but if you haven't kept up with it its not recommended as the new fluids can cause issues.

Curious has anyone encountered total failure from replacing the fluids on a car that's never been done or at higher miles? The lifetime fluids BMW state is a joke. If I owned this from day 1 I would have done it in increments but since its new to me I figured it was never done.