Not merely threats to the postal service itself, but threats via the postal service. I imagine the best to get away with (say) fraud has always been to avoid physical presence, i.e. using mail.
This is the territory where police departments and agencies get themselves into trouble - investigating crimes that aren't really their job to investigate. They technically have jurisdiction over a specific location or process, and that gives them an excuse.
The most obvious parallel is pretext stops - state cops, sometimes local, coming up with an excuse to pull someone over on a highway, in order to check them for warrants or in hopes of discovering contraband they have no reason to suspect exists.
A less obvious example is immigration enforcement fishing for excuses to deport someone.
The most obvious parallel is pretext stops - state cops, sometimes local, coming up with an excuse to pull someone over on a highway, in order to check them for warrants or in hopes of discovering contraband they have no reason to suspect exists.
A less obvious example is immigration enforcement fishing for excuses to deport someone.