slightly clearer filtering for super users

It will. I had this problem in https://bugzilla.mozilla.org/show_bug.cgi?id=1039026

had to solve with this.... https://github.com/cadecairos/webmaker-events-service/compare/mozilla:84289fa...cadecairos:b22644d#diff-94f535daa08bee6974fb91341f39304eR258