When MTA loads its in-game Masterlist, the client gives it 20 seconds to respond. It then posts the response, and stores it locally. Conversely, when there is no response, it displays the last recorded Masterlist, with a footnote saying contact to Master Server failed. This fake masterlist is inaccurate by player count, but generally 95% accurate regarding servers, and most importantly 100% usable all the time. I have seen them use it for days on end when the situation called for it.
Without live data, sorting correctly would become an impossible task. That, and when all services are unavailable, one can’t connect to servers anyway - so it isn’t really worth putting effort into any sort of fallback.
Also, antivirus software hates it when an app directly queries every server IP it knows of and starts heavily complaining.
On Multi Theft Auto, any user can connect to any server they have never been to before, on any day the Masterlist is down, which for FiveM it was for at least 24 hours, where only the most regular players were joining via another means.
No one asked to sort correctly. Only to provide the less capable user, an easy long list to replace no server list at all.
All services were available, but there was no masterlist therefore only a small percentage of people were connecting. This has happened before, and will happen in the future. Toward such not happening again, having a backup client side masterlist, will prevent further attacks, because attacks are only effective when they damage a system. With a fallback masterlist stored client side, an attack cannot do the same amount of damage.
When MTAs masterlist is “down” we lose 10% of our traffic, when FiveM’s list is down we only keep 10% of our traffic.
There is no need to query any long list of servers. MTA displays the old server list as it was displayed on the day it was accurate as though they regularly display whatever list already exists client side all the time, updated or not. Most clicks will connect to a server, some will not connect to anything, the number of users will be inaccurate. But generally speaking, life goes on as normal, as your attackers failed to damage you.
So the request isn’t really will you add a client side backup masterlist, but rather do you want to continue to reward your attackers with our suffering? Because that is what you offer them now. Attack us and watch us suffer, because we have no fallback system.