A heretic non priest thought he did, and so did I at the time. However I have since learned better (and found out that he did not do it according to the proposed method). I no longer have that scapular, but I wear the replacement continuously.
I do not know if it can even be properly called a sacramental in my case, since it is not blessed, nor was I enrolled in it by a Catholic clergymen.
It is a reminder to me of my duties to the Blessed Virgin Mary and it reminds me to invoke the Blessed Virgin in times of temptation.