I'm going to be going with my daughter's class at school on a field trip to Washington DC in a few weeks, and knowing it's not the safest city in the world (by a long shot), have been thinking about self protection. We're going to be doing all the usual "touristy" stuff like visiting Arlington, the Capital building, the usual landmarks around the Washington mall, and the Pentagon, I think. Obviously, I won't be able to conceal carry in any of these places, but what about the folding knife I ALWAYS carry? Does anybody know if any or all of these places use metal detector screens? If I can't even carry a pocket knife, is OC spray an option? Other ideas? Thanks!