Let me set the scene:
You are a staff member or owner of a group with five thousand members. During a group event, a member, henceforth referred to as Joe Shmoe, accuses another user, henceforth known as Dudebro McGee, of stalking them or doing something else creepy, rude, or otherwise generally disrespectful. You have no proof any of Dudebro's alleged actions are true, so it's all hearsay. You do the smart thing and alert the rest of the group that there's someone by the user of Dudebro McGee that needs to be kept an eye on due to the allegations of Joe Shmoe. Then suddenly, a month later, you notice that Dudebro McGee isn't present in the group member list and that nobody has left and/or joined since Joe told you about what Dudebro did to them. Regardless if you had put a note on the user or not, it would take ages to sift through all five thousand members to figure out which has that note if one was made.
I propose the following: the ability for certain modertor/staff roles within a group to be able to assign specific colors and/or symbols to specific roles for assisting group moderation.
Implementation:
For colors: An assignable hex code to specific roles, with an option to auto outline in white or black as needed.
For symbols: A set of predefined symbols, like a pair of exclamation marks, a No symbol, an X, and a checkmark, among other simple symbols.
For both: The ability for, using toggles that the group owner has to set, to assign
  1. Who can see certain role colors/symbols, like if every group member can see it or if only certain staff roles can.
  2. Who can add/remove role colors/symbols.
on top of the colors/symbols viewable both in game, in at least corresponding group ran instances, and on the website.
Preferably: Both should be implemented to allow for even colorblind users to identify things, as well as for those who might not have the best eyesight when it comes to small symbols.
Why do this? This should be done in order to help make things easier on groups so that people who are known to be frequent username changers or who might change their name to evade moderation can be tracked better, that way you can instead give group staff members a color/symbol meaning list instead of having to constantly update people on what new name an individual they need to monitor is using.
Do note: This is aimed at groups who might have someone concerning they need to monitor, but has not caused anything warranting an outright ban.