It’s a silver lining to see Shatner using his platform for the greater good.
I recently learned that Shatner and Takei don’t actually use social media and all the posts you see from them are just some employees that were instructed to speak in their style.

It’s possible on a regular basis.

However, as with other high profile accounts, one expects that messages that are high profile would be cleared with the person under whose name the official account is made.

Not at all. Chapelle told that joke about hearing that “his” “official” Twitter account was having beef with Kat Williams’ “official” account. During one show when both of them were in the audience, he went over to Kat and told him the situation - to which Kat replied, “wtf is Twitter?”