This is also why ANet doesn’t have official RP servers. It would mean that they basically have to take a stance on what RP is and isn’t acceptable, shut down personal RP stories that don’t coexist nicely with the Personal and Living Stories, and generally introduce a whole bunch of restrictions which would really crimp player creativity.
I always do my best to have my personal RP stories match with lore, but if somebody else wants to RP their Sylvari as having been adopted by a human family, I don’t see why not. Their RP can take place in their own headcanon world with their friends/guild; it has nothing to do with my characters, and we can both enjoy ourselves without infringing on the other’s story.