Shemitah in the Diaspora II

R. Hershel Schachter explains his view that even one who does not rely on the heter mekhirah may purchase and eat produce from a farmer who does (and, presumably, treat the food with the proper holiness of shemitah): link. He bases this on the Mishnah Berurah (318:2) in the name of the Pri Megadim, that whenever there is a dispute among the posekim about a prohibition then the lenient view -- even if you do not follow it -- prevents food produced in such a fashion from becoming prohibited [R. Schachter doesn't say which Mishnah Berurah but I believe that I have identified the one he means].

See also this post.

When I was first married, someone once gave us a Jaffa orange on a Shabbos during a shemitah year. I asked R. Feivel Cohen on that Shabbos and he told me that the orange is muktzeh because one is not allowed to eat it. Not only would R. Schachter say that it is not muktzeh, but he would allow one to eat the orange even though he does not follow the heter mekhirah.