Turn this option on, and set range at 150-900ms. You won't be able to fight anyone if the server is at 4k people on.
Set it at 300-900, and you will not be able to fight delayers/laggers at 4k people on.
During night time for PST (8 pm - 8 am) set it at 200-900, and you will not be able to queue against delayers/laggers (server is below 3k)
International people will be able to fight anyone they want, the server will just limit people who have this option on, to not allow themselves to fight delayers.
This is so people don't have to worry about checking if someone delays/check their flags, and only want to fight against people with a clean connection.
If you can't spar anyone, you simply turn it off and risk your own neck.
Btw... this is only so you don't have to worry about the people who Delay + Are using something to make themselves warp, like a lag switch.