We have the same issue with the FDL that we use and I believe it is a Registered with the specific design and colors. We should be able to do the same thing with CAJUNS.
The University of Texas has the same issue with Longhorns. Anyone can use Longhorns and it is not protected. The more Longhorns is used outside of the university, the more publicity the university gets for itself. The same applies to use of Cajuns.
My preference would be to get away from the old, worn out block Ragin Cajuns and continue use the script Cajuns, but dot the "J" with a small FDL instead of a star. And, when using Ragin Cajuns, make it in the format used for the script Cajuns.