Many years ago, I had a good friend in college was a very talented artist. She was invited, while a sophomore, by a teacher to take one of his graduate seminars in painting. When she showed up at the registrar's office with the schedule approved by her advisor, the registrar... this very lady... refused to allow it.

"You...you can't DO that! You have to be at least a junior or senior to be in that class" (something like that)

"But I have permission, and the teacher has final say over these things...I think that regulation is only guidance."

"But...but ...it's against the rules!! No,,it..." and so on. The woman was practically apoplectic and had to be led to an office by other staff to settle down. Eventually, the teacher had to come over and personally insist that my friend be allowed in his class...and she was.

The registrar was very good...and VERY rigid about 'rules'. I'd hate to imagine her at CitiBank, dealing with death and overdue charges.