Phishin:
I totally agree with you ;-) If you have your tranny flushed on a regular basis from the time the truck is new - it should be fine and will extend the life of the tranny. However, for someone who has never had this done this before, many shops will recommend it after lets say 150,000, never having had it done before. There is buildup in the tranny that WILL come loose and COULD harm the inner workings.
So to clarify:
If you buy a new truck and choose to have the tranny flushed on a regular basis, go for it. Thats a good thing.
If you have never had it done - DON'T.
Ok?
I shouldn't have spoken in absolutes - my apologies - i was simply responding to this posters particular situation.