In the parkour server if you select the option to hide all players, it only hides the players that are currently on the server; you can still see players that join the server after selecting the 'Hide all players' option. I suggest that it work the way that it does in hub lobbies, where if you select 'Hide all players' then it actually automatically hides users who join the server afterwards. I hope that made sense.
Here's a sped up video of the way it works currently;
https://www.youtube.com/watch?v=9wXbqqYSH0E&feature=youtu.be
Here's a sped up video of the way it works currently;
https://www.youtube.com/watch?v=9wXbqqYSH0E&feature=youtu.be