I've done that a few times on purpose to mess with the new LT's.We were in the back of a deuce and a half, watching an e-4 walking down the sidewalk with a laundry bag over his right shoulder. He was meeting a captain walking the other direction. When they met, the e4 saluted smartly and said, "Good morning, sir." The captain returned the salute, walked a few more steps, stopped, turned around and gave the e4 a really funny look. Did he really salute with his left hand???? All of us in the truck were about to bust a gut laughing. I guess it ended up, no harm, no foul.
We used to send troops to the motor pool with a hammer and a piece of chalk to check for soft spots on the armor and mark it with an X.