It is because the school accords them such luke-warm treatment that they get "fresh" and start "Guying" the night watch.
"Botchan (Master Darling)"
Mr. Kin-nosuke Natsume, trans. by Yasotaro Morri
"I reckon folks have been Guying him.
"Dixie Hart"
Will N. Harben
The man who told him this grinned, and evidently considered it a good joke, nor had Peter been unconscious that all the morning the clerks and underlings had been laughing, and Guying him as he waited.
"The Honorable Peter Stirling and What People Thought of Him"
Paul Leicester Ford