SE bans twitch streamers but not actual cheaters?

[Pells]

The difference is that the undercutting bots aren't announcing to the world that they are in flagrant violation of the TOS unlike Twitch streamers.

The secondary problem with the undercutting bots is that at a glance, nothing they are doing is against the TOS. Standing around isn't against the TOS. Being located near a summoning bell isn't against the TOS. Listing items on the MB isn't against the TOS. Undercutting by 1 gil isn't against the TOS. However, it is the bigger picture of the situation (standing at a summoning bell for hours (days?) on end, relisting every few minutes for the lowest price) that makes it humanly impossible.

Good luck getting a GM to sit there and verify this long enough.

They'd probably fix the problem if they converted the MB into an Auction House instead (FFXI style). And charge an upfront listing fee, so every relist kills the profit.

How do you know what their retainer names are? All you're seeing is somebody standing there for hours on end. You don't need a bot to afk.