McKinney is encrypted, Collin County is not. Plano, Allen, Wylie, Murphy and the other communities on PAWMCo encrypt their NCIC/Inquiry channels, but dispatch is clear. Frisco/Prosper is clear.
Celina stood up a new NexEdge system recently, and my current antenna setup doesn't give me the range to pick it up from home (I barely get the Megahertz Tier 3 and Connect Plus regional systems out of Howe), so I don't know if its public works only or if there might be some public safety on it as well (most of Celina mostly is dispatched by Collin County so I doubt it but need to investigate to be sure).
I too would be interested in hearing the reasoning behind VA's encryption. I'm walking distance from home to Braum's and see accidents on the 75 service road all the time, but it would be nice to know when I need to plan an alternate route when inbound from McKinney on 75.