If they deny their existence, how do we know what they are called?
You haven't ever seen a NOAA LEO? They are armed and they routinely board and inspect commercial fishing vessels... Oh and the ammo was hollow points... They stop faster in the confinement of a steel ship.
They look like this: Office of Law Enforcement
But Law enforcement isn't the only thing they use security for... Piracy is big business these days and there are many who would love to capture one of the NOAA's multi-billion dollar Research vessels.