This is a separate problem with the legal system -- it fails to properly calibrate the definition of "reasonable search" to the case at hand.
I'd have no problem with a legal doctrine that says that the cops need less evidence to search for (e.g.) terrorist preparations than to search for (e.g.) somebody's pot stash. Of course, the doctrine would need to be backed up with corresponding exclusions (e.g. if the cops went in looking for a pony nuke based on minimal evidentiary support accepted in such cases because of the public safety issue, didn't find a pony nuke, but did find pot, they can't use it even if it was in "plain sight" once they got into the house).
'This is a separate problem with the legal system -- it fails to properly calibrate the definition of "reasonable search" to the case at hand.'
I agree with your dual point here -- i.e., both that 'reasonableness' should be calibrated to each case and that this is a separate problem from the one under discussion.