"On Guard" has been used three times by Q. I fenced intramurally years ago at university. I can't help wondering if someone in Q fences, or maybe was once a pentathlete.
In fencing, the ref issues the On Guard command and fencers ready their weapons in sixte awaiting the start of the bout. Then the ref queries Ready followed by Play (En garde! Prêts? Allez!).
I've been looking for fencing timing and point markers in relation to the On Guard comments but have come up empty so far. Any other fencing anons care to comment?