[coldcode]

If it affects flight stability especially in an emergency, then pilots should be trained to understand what it affects. Period. Not doing so to save money or get more sales is beyond stupid. Watch Air Disasters to see what happens when highly trained pilots fail to do the right thing because they hadn't trained to deal with what went wrong because the problem was something different than what they knew. Flying is easy when things are working, pilot training is the difference between dealing with an emergency or being dead.