Fair enough. I for one have no intention of hiding from or avoiding any checkpoints. In the case of a terrorist attack I would fully expect the authorities to attempt to make damn sure no suspects were able to escape by mixing in with the refugees. In that case I might consider a rather rigorous search to be reasonable, after which I would expect to be allowed to continue on my way.

Of course I might change my mind if it appears that weapons, supplies, or anything else is being confiscated, a la Katrina.