Ok, sometimes odd things pop into my head when I am lying awake at night. Last night, I was thinking about what to do in the event that some wack job showed up at the hangar with a gun. (Answer - throw the keys at him/her/it and run to minimize the risk to me and to others). But if we did end up in the air and they were demanding to fly to Billings Montana, would I squawk 7500? I decided - no. If I did, you would get a call from ATC, and I would answer that you intend to squawk 7500 - right? Then what? I assume I would get intercepted. But what good would that do me? They would try to get me to land somewhere and probably get the "bad person" all agitated and likely to shoot me. If I attempt to ignore them, then they either do nothing (big help) or shoot me down. One has to consider that the intercepting pilot (or whoever is giving the pilot orders) might be a trigger happy hero with visions of 9/11 dancing in their head... Either they do nothing, or they kill me. Why would I ever want to squawk 7500?