Is it illegal for someone in a foreign country to photocopy my material without permission?
Not necessarily. Copyright law in other countries can vary greatly from U.S. copyright law. For example, content users in some countries do not necessarily require permission be obtained from any rightsholder or creator to photocopy printed material. Instead, the laws of these countries include "statutory licenses" that give users the right to photocopy material on the condition that they report that usage and pay royalties (which are often set by the same statute) to an RRO. Therefore, although the RRO in a particular country may not have received authorization from you or from Copyright Clearance Center to license your work, it will have collected photocopy license fees with full legal authority in its own country.