patch with #

[Nevadaref]

Watched the Cal-UCLA game earlier today and noticed that the Cal players are wearing a small, square black patch on the upper right of their jerseys. It has "AL" with the number "31" below the letters on it.

I know that under NFHS rules the presence of the number on the patch is illegal and results in a T on each player when they enter the game. However, I looked up the NCAA rule and it does not prohibit numbers on the memorial patch.

Anyone know why the difference?