Nevertheless, the Mishnah Berurah (s.k. 5) rules that wearing tefillin publicly, even without intent to fulfill the mitzvah, is an issur d’rabanan of maris ayin (doing something that appears to be forbidden). We conclude with a very pertinent halachic consequence of our discussion.
Tefillin Are Not Muktzah
The Acharonim debate whether tefillin are muktzah since it is forbidden to wear them on Shabbos (see O.C. 308:4). The Biur Halacha writes that since it is permitted to wear tefillin without intent of fulfilling a mitzvah, they are not considered kli she’melachto l’issur (utensils of forbidden usage), and therefore are not muktzah. In cases of necessity, one may rely on this reasoning. For example, if one finds tefillin in a forest on Shabbos and fears they will be desecrated, one may wear the tefillin as clothing in order to preserve them.