Comment by mokus

If it's obviously a sham (like your yarmulke example) then sure - it shouldn't fly. They'd be right to point out "that isn't even your religion, and we have evidence X, Y, Z that proves it."

But if a person practices a religion imperfectly, to propose that their continued attempts to live by it are null and void? That's ludicrous. Moreover, it would also constitute the government telling you specifically how to practice your religion, which is to my mind even worse than forbidding it in the first place.

(EDIT: minor continuity fix)