I misdoubt that any Guardsman, nor any other serving soldier, sailor or airman, would accept your statement of "give them a break" with any appreciation in this instance. Even if it was a pouring deluge.
I include this assemblage of a series of videos showing the Guards of old.
I am quite sure a tunic belt worn incorrectly would in any circumstance elicit a very stern response in these days.
https://www.youtube.com/watch?v=nfPYj1vLBDA