It would deal with the rampant botting and cheating though, but that's a separate conversation.
This the issue, the client does not need the accountID to do anything as it isn't interacting with the other player's account, it's only the character that it sees it needs to check. The accountID should be a server side check with anything requiring the use of account id being managed through a characterid challenge from the client.
A basic pattern of security is least privledge, the client should never have read privledge on account ids of other people.
If they wanted to fight bots they could apply a number of server side heuristics to prevent them from teleporting around, from getting under the map, from speed hacking. Same thing as the blacklisting issue though, it would increase the server costs and evidently they are content to let people believe that nothing can be done, rather than outright tell us "it would cost us money so fu"
Well, one thing you gotta remember is that the whole teleporting around has been used by staff in preparation for Fan Fests. Does that excuse bots from using this channel to level characters? Of course not. My concern would be that if they decide to implement something more instant, then that would likely allow people with malicious intent to figure it out and deploy their bots to use that, too.
Or maybe that's already happened and people who are on the surface level just don't know that, yet.
Anticheat wouldn't work for this. You can access this information without tampering with the game's files via Wireshark. You don't even have to directly interface with ff14 to get someone's account ID. Hell, you don't even need to have ff14 installed on the same machine that ff14 is running on. Until that information is not shared with the client, no anticheat or attempts at stifling plugins or mods will ever work.
Well, if the check is server side, they could just enable a flag server side for specific Square Enix Accounts that says "yeah, this character is allowed run underneath the map at 500% speed, this is gucci."
And if that flag is set on an account basis, any account that does the same thing without that flag could get tagged for investigation. Automatically. Its a much more elegant solution than trashing customer computers with a useless anticheat application.
I'm not talking about those bots. I mean the ridiculous number of players botting things like diadem/firmament, and general crafting/gathering, and HoH for the accursed hoard achievements, or fully automating their rotations in raid content.
I don't think people realise how much these plugins can do or how many people are using them.
I take it "Fixing the issue" isn't on their radar?