To avoid any situations (and we all know that will happen), it should be in your by-laws. You should define what a teacher is (as opposed to a quilting day where folks are just assisting each other). It should also state what compensation a teacher should receive. The amount does not have to be listed, just if it is to be a gift card/present or a monetary amount to be determined and voted on by the current board. If your bylaws do not have a provision, the current board can vote for an amendment to be added. At this point, anyone filling the criteria of the teacher, is considered a teacher, whether they are a member, an officer or an outside person. But, when that member or officer is teaching the class, they are doing so as a teacher, not as an officer.