That is not the case anymore. Five years ago, yeah, you had to have a department email to sign up for policeone and blutube, but not anymore. You can sign up as a "police associate" meaning a dispatcher, or civilian employee of a department which is not vetted. Now, there are more associates posting than vetted cops.
But, a lot of the cops that post there are aggro pieces of shit from what I have read, which is why fewer and fewer cops actually post there anymore.
Policeone is a very good site, especially for the online "policeone academy" five minute videos. They are perfect for role calls. I usually show one of those videos and maybe a humorous or intense video from the regular site, then maybe tell a story about a similar topic, or ask one of the officers if they have encountered similar.