Sounds like the management of the various agencies is the root of the breakdown in interoperability and NOT encryption. If all your chiefs and managers were on the same page about what the ultimate goal is here - public safety - they'd get their act together and create the SOPs and channels required for multi-agency responses. EMS should always have PD respond when the call involves a violent patient. If they don't as standard practice, then they have another policy to work on.
You seem to misunderstand. I CAN currently monitor PD & FD, I can also monitor PD, FD & EMS of every member community of the Homeland Security Region on my department portable. I can also monitor them on the VX3 that I carry in my pocket while working, and on my HT1550XLS. I used all three at a 5 alarm fire the other night.
The person I was replying to is a supporter of encryption for PD, and doesn't believe that encryption hinders interoperability. I know that the PD would never give out their encryption keys if they were to implement them, and that person also believes that a talkgroup should be designated for the incident so that everyone is on the same channel. They don't seem to appreciate that in a city of over 600,000, with 100,000+ EMS calls and 800,000+ PD calls annually, that it just isn't going to happen. They also don't seem to understand that each individual agency has it's own licensed frequencies, and their own system managers. We don't have talkgroups, we have channels. The system works fine as is, and I'm not saying it's broken-the person who's feedback I'm requesting is.
As far as getting the cops to go to their calls, that's a whole different story.