As we saw in the questions surrounding the matter of trunk searches during traffic stops, the issue of reasonable versus unreasonable becomes a matter for the judiciary. We have to be vigilant in the protection of rights.
I don't know if I can quite accept that. I know they've claimed that power for themselves, just as they've claimed lots of powers for themselves. But I've always understood "unreasonable" in this case to simply mean arbitrary searches and seizures that would be illegal for any private citizen to commit against his neighbor. I put not my trust in the judiciary to "modify" it any further than that.
I agree with the "vigilant" part, though.