Hey guys, back on the original topic, SPEN 2 is also considered the "NLEEC" (National Law Enforcement Emergency Channel) and every law enforcement agency can participate in their respective states' plans for using it. Usually the state police or highway patrol administers the plan. The NTIA also allows federal agencies to come up on this frequency. So, it's pretty much a nationwide common ground.
All sorts of matrix boxes ("JPS", "ACU") and console cross-patches (most consoles from Zetron all the way to Motorola can patch one channel into another just with the dispatcher pressing two buttons), it's pretty easy to come across something you don't expect. With so many of those out there, it can be difficult to know whose it is, how it's authorized, and who can set it up or shut it off if it's needed.
The rest is conjecture. Might have been a joint operation, might have been a test, might have been messing around. Might have been a mistake.
Reeeee-co-laaaaaaaaa (SPEN 1).