Assuming that Bazzet wasn't lying when she spoke of reports, her superiors in the Magus Association know about the Class card inside Chloe
So, at least in the timeline based on the assumptions I've made, something like this has happened.
Dear Magus Association.
As a father, one is both proud and saddened when his children prove capable of fending for themselves, and as a father of two wonderful girls and a fine young man, I am no exception. However, there are some things that a father never wants his children to have to do, and some things that a father must do for the good of his family, even if his children wouldn't approve of it or believe that they can take care of it themselves.
I don't know which faction is doing it, but if one more person shows up trying to kill my children to harvest a mystic code from one of them, I swear to God I'll fly up to London and start shooting random magi until I hit the one in charge of this mess. You know what I did to the Einzberns, and they were family. You're not. Think about it.
Sincerely, The Magus Slayer.
PS. Enclosed is a matchbox containing the remains of the last magus to try and harm my family.
PPS. If a certain young lady reads this, write more often. My girls miss you.