I understand the importance of scheduled demonstrations & we predominantly use only planned demonstrations. I teach in a medical program though, sometimes very dependant on the cases that walk in the door & when they do come in as to the types of tests/procedures we will be doing. (they don't always come in on the days of parasitology lecture or hematology, etc.0 Typically, the other main instructor & I will try to gather as many students as possible if we have something unusual/unique. This can involve "rounding up students from the lounge". After reading the material on demonstrations, should we not "disrupt" the students? We tell them point blank when they enroll & during the classes that if something "cool" comes in, we'll show as many as possible, even if they aren't in that course. They may not have that opportunity again. Should we approach it differently?