ATTENTION! (Also known as "The Case of the Mysterious Salute")

I'm not sure if there's a joke being played on me, or if I've all of a sudden turned into a scary dictator, but for some reason a few students (all boys, of different grades) have been standing at attention and saluting when I'm around.

Evidence:

Weird Salute #1: Yesterday, a cheeky Grade 2 boy saluted and yelled out "YES SIR!" after I gave the class instructions to tidy up. (Note: this did NOT go over well, and we hat a nice little chat after school).

Weird Salute #2: Also yesterday, when doing attendance in a different class, a Grade 3 boy stood up and saluted "Here" and sat back down.

Weird Salute #3: As I walked down the hall today, a grade 6 boy stopped what he was doing and stood at attention, hand in salute position at his temple.

Fact: None of these boys are friends, nor are they in the same grade.

Question: Is the salute the new "Hi" when encountering someone you know?

I'll keep you posted on this unsolved mystery.....