Right now we can count ourselves lucky that there's a voice of reason at CBS Legal who cares about the difference between free positive publicity and actual attempts to profit from something related to their IP.
Quite true. CBS is being very generous to Star Trek fan films right now. Sooner or later, this may change.
Of course, in addition to Project: Potemkin, I've been publishing fanzines since 1979, and have never once been bothered by Paramount, Gulf+Western, Viacom or CBS. Although one of their licensees got a bit litigious over the name of our fanzine, I've had nothing but cordial dealings with them for Orion Press for 35 years.
I'm hoping the same holds true for Project: Potemkin and all other fan films.