Color coded clarinet

She was a new student who transferred in. I needed to listen to her so I could place her. I had never seen color-coded keys and it gave a good reason to have a nice get-to-know-you conversation. She said her band teacher labeled all their clarinetists’ keys like this. It was a nice horn.
Wow! I’ve spent my whole teaching career explaining the fingerings and expecting students to get it.
I HAVE had students label all their music notes. I didn’t allow it if I knew about it…..explaining that they were going to encounter more notes than they were going to be able to label.
btw I wonder if that teacher labeled trumpets or trombones.