You are absolutely right. Mr. RightField has taught high school for 45 years and knows the value of respecting and maintaining a good relationship with the custodians and the food service people. It is always a win-win situation.
Unfortunately the janitor is a long time target of Hollywood for painting as the buffoon.
In my experience they’re some of the most solid common sense minds in a school building or anywhere else. (I did a few years as a school janitor myself)