That isn't true. Our sheriff's office (SO84DISP) can patch their TGID with MARIETTA PD 1, BELPRE PD, and POST84 any time they need to and they also test the patch on a monthly basis. They can also patch the county MARCS fire channels into the UHF channels whenever a unit with an analog radio needs to talk to someone on MARCS.
Maybe that's only in your county? Our county always patches whenever necessary and it's a good thing they do, because they're using MARCS more often but not everyone has a P25 radio yet, so the easiest possible way to provide interoperability in emergencies is by patching the MARCS talkgroup being used with the UHF repeater being used. I mean, the units on MARCS could switch to the UHF channel, but there's a possibility that one or more of them might miss the command to do so, thereby causing a communication issue. And that's the last thing any of us need in an emergency.
Not true, see attached policy.
I doubt that would be them on MARCS. Cleveland once told my old agency that they could not interop with us because they do not go on to MARCS and will not pay the fees. I would guess that it is MARCS themselves. It shows 1106 in the wiki being the helpdesk so it isn't far off.
How does their system work?