In my experiance assisting with Motorola P25 system build out, radio techs like to use Encryption for testing. There are a number of reasons, 1 it's kinda cool. 2, it tests the encryption features like Over the air Rekey, etc, and lastly, anyone who happens to have a demo radio that isn't keyed can't hear field testing. You kinda don't want end users to hear about field testing, things can be misunderstood or misconstrued during testing and rumors can fly.
I once heard a story from a legendary P25 specialist who told me a story about a massively expensive multi site simulcast city system that was nearly torpedoed before they even started doing field testing in earnest. A fire chief (or maybe it was police, I forget) who didn't want a p25 system had a demo radio set to scan sitting in his office and heard a tech say "wow, there's no coverage anywhere in here" on a testing channel sarcastically in the basement of city hall (ironically where the Chief's office was.) The fire chief threw a world-class fit and wanted the whole system removed, effectively throwing away millions before all the sites were even turned on. Luckily, a couple city council members thought he was a little hasty and wanted a second opinion.
Eventually, they were able to prove to him that it actually had better coverage than the aging VHF voting system they had by calling in a third party RF coverage vendor who tested both systems in Gov buildings and it some office and hotel buildings on the outskirts of the city. Around this time, a storm knocked out power to the radio sites for the aging system, but since they had just added a new generator and UPS system to those same sites for the Trunked system, city electricians were able to temporarily move power off the old Generator/UPS System and onto the new UPS/Generator system for the trunked system. The combination of the 3rd party coverage vendor and the power outage was enough to convince him to call off the dogs. But it cost the vendor and the city thousands of dollars. (and the project went from coming in under budget to well over budget) But it just goes to show, just the perception of the system not working during testing can be a big problem.
The state is not going to pay for encryption for the majority of users of this system. It's just not going to happen. The system is expensive by itself, to get the licenses for encryption, OTAR for every user is cost prohibitive, especially at the per radio subscription costs they have set forth. I can see DOJ and other "secret squirrel" Law enforecment talkgroups being encrypted (CHP Dignitary Protection) but that's about it.
It's good to log the Radio IDs and Talkgroups of all the traffic on the system because it helps us get a good idea of who's a radio tech and who's not, what are their channels, etc.