High Security Relevance
This setting is important for the security of your server!
Use it carefully! Wrong settings may make your server vulnerable or limit its functionality or accessibility!
Control if you want the U.S.G.N. masterserver to check U.S.G.N. login IDs before a player joins (1, default) or not (0).
Note: This setting does not matter if sv_usgnonly is set to 1. In this case a check will always be performed before a player joins.
Attention: IF DISABLED: Disabling this check can be a security risk. The check will be performed nevertheless (delayed), but the player can be on the server with a wrong U.S.G.N. ID for several seconds (depending on how fast the masterserver is able to check the login). This can be used to hijack servers if there are Lua scripts which only rely on the U.S.G.N. ID to give special permissions.
Attention: IF ENABLED: Enabling this check (default) can slow down the join process because each player with U.S.G.N. login must be checked by the U.S.G.N. masterserver before they can join the game.
Consider to disable this setting if you are not using Lua scripts or server settings which rely on the correctness of U.S.G.N. IDs.
Also some players reported that they are sometimes stuck in the U.S.G.N. account verification screen - those players should restart the game and try again later.