I've had this q for awhile and since I know you (I think?) started in Star Trek fandom I'll ask you. Was there any RPF going on or was it seen as anathema? Was there a small sect that shipped Shatner/Nimoy? What do you think of/where did RPF start?
There was RPF but that’s not the same as RPS - I myself do not recall any Shatner/Nimoy but there were these famous RPF stories particularly those where the Enterprise Crew were switched with their actors, like in the SPN episode. Visit to a Weird Planet was one. Galaxy Quest before Galaxy Quest!
In my recollection, RPS existed but was considered to need all these additional special protections (the name changing of Trix/Alex for example) and it wasn’t really until popslash that most people sort of decided it was okay so long as the public persona was sufficiently mediated–I mean, NSync were great for that since they literally framed themselves as puppets: you can’t give fandom an invitation like that, we know what to do with Barbies, right? I think fandom still –okay, now I’m going to philosophize - but I think fandom is divided and confused on the relationship with celebrity and if anything it’s gotten a bit worse now that you have this blurring of private and public spaces, commercial spaces and fannish spaces, etc. I also–and this is me, my own thing here–but I have my own feminist issues with the objectification of celebrities in certain contexts, especially mainstream ones like photoshoots; one of the things I like about fic is that I see it as an exercise as subjectification rather than objectification, but that’s a subject for another day.
Starsky and Hutch fandom also had some early RPS in the 1970s but it was very much under the table (keep in mind that a few fans tried to make trouble for the first slash fanzine publishers in Starsky & Hutch fandom so you can imagine how tricky it was to acknowledge RPS).
I know of at least one US slash convention that struggled over whether to allow RPS panels for fear of liability (but apparently live demonstrations of BDSM techniques was fine). Still by 2003 they had RPS panels so the struggle was brief.