There is one PVP server with a decent amount of people on it. I have two groups of WoW friends, all on Nightslayer and half are alliance Half are Horde.
I think in 2024 we dont really have to worry about people hanging out in enemy cities on sleeper accounts spying waiting for large raids to form for enemy faction cities.
Cmon now, let us play both factions, the server has 60K people on it.