Perhaps a more generic warning in the default verbiage, that once vanished you will not be able to submit any type of requests.

In T401869#11085491, @Xaosflux wrote:

Perhaps a more generic warning in the default verbiage, that once vanished you will not be able to submit any type of requests.

IMO, the message should also point out where the username will not be automatically changed (eg. file attribution, pings and signatures in discussions).

And I think that a request to change the name in signatures may be not so problematic as changing file attribution and can be made on request that does not need identity confirmation (The CC "attribution" for wiki edits is considered to be in the page history, not in signatures).
Personally, I would have no problem to handle such request from a non-identified vanished user.

Perhaps better clarification on what will be changed? (i.e. only metadata and User:USERNAME page titles). No "content" is ever changed by way of a rename/vanish.

FYI: This topic was discussed at a stewards meeting today, follow up is to open a discussion about ways to improve the default warning text when users request vanishing.

A community discussion has been opened here: https://meta.wikimedia.org/wiki/Wikimedia_Forum#Improving_the_warning_text_at_Special%3AGlobalVanishRequest

Please provide feedback, thank you.

@Ankry - perhaps you could advertise this at commonswiki

In T401869#11087686, @Xaosflux wrote:

@Ankry - perhaps you could advertise this at commonswiki

https://commons.wikimedia.org/wiki/Commons:Village_pump/Proposals#Account_vanishing

I think the wording should explicitly cover that a username change re-attributes all previous contributions. For edits, this happens automatically since the attribution is stored in the page history, and by requesting a rename/vanish the user gives permission for that automatic re-attribution. For files, however, attribution is usually stated in the description page and does not change automatically.

The vanish/rename message should therefore not just be a warning, but a clear statement that by making the request the user gives explicit permission for us to:
(a) automatically re-attribute their edits under the new username,
(b) reassign file attributions to the new username if we choose to do so, even though this will not happen automatically, and
(c) allow such reassignments to be carried out later either on their own instruction before vanishing, on request from others, or as part of routine community maintenance.

This ensures the necessary permission is recorded up front and avoids situations where we are unable to correct attribution after a vanish because no explicit permission was captured.

An indication that uploads at Commons are not adjusted perfectly. The different treatment of Contributors (altered) and Authors (not altered) is a frequent gotcha for people trying to lose an association with their previous name.
https://commons.wikimedia.org/wiki/File:AliceAyres.jpg ties me to a username from 9 years ago.

In T401869#11127354, @Cabayi wrote:

An indication that uploads at Commons are not adjusted perfectly. The different treatment of Contributors (altered) and Authors (not altered) is a frequent gotcha for people trying to lose an association with their previous name.
https://commons.wikimedia.org/wiki/File:AliceAyres.jpg ties me to a username from 9 years ago.

Contributors and authors must be treated differently: the contributor is not always the author. Contributors often upload third-party content.
While renaming accounts, users should be aware of this difference.

must?
Where the author is populated with a username link it's not impossible to have it updated. Certainly more onerous on the system, but not impossible.