Questions coming from a couple of long time PSU players.

@Ler You can go to any player's room anyway, unless they locked it, just check their profile and go to room. But room being a premium thing, most non premium players will have their premium room locked unless they activate a 3 day room ticket (those are easy to get, no RNG involved either other than obtaining excubes for the exchange). The visiphone also has a ranking for rooms, so it's possible the most visited rooms have the premium room active at that time.

I totally forgot about the mission lobbies in PSU.

I haven't seen the challenge room yet or the guild one, but yeah the rest of the lobby is pretty big.

Was there there a soccer field lobby or something funny like that temporarily at some point on the JP servers? Or have they made temporary areas for events?

@Hengbok The ball and two goals are in front of the concert area, but it disappears as soon as Quna spawns.