Idk about others but from my experience in Phoenix, hardly anyone joins in on Fates, especially near La Noscea. I usually get killed because I'll be one of like 3 people fighting alongside NPC's. We do get a few that are way overcrowded, but rarely do I see those. It's usually just a few people. Just my experience though, it also depends on the time you play and I usually play around 1am-5am.