Tick or Untick Game mode?

I have a doubt: how should be this setting, ticked or unticked? When unticked, using a full screen program or game, the game mode is enable?

If you enable “silent/gaming mode” then no pop-ups or alerts will be made.
IOW, if there is a possible threat you will not be alerted. If you are a gamer
and offline and you know the game is safe then you can enable silent/gaming
mode. If you are online and playing a game leave it disabled.