https://musicbrainz.org/doc/Style/Titles#Extra_title_information currently says,

Additional information on a release or track name that is not part of its main title, but intended to distinguish it from different releases or tracks with the same main title (such as version/remix names or live recording info), should be entered in parentheses after the main title.

There is no caveat that says you can delete "remix" or "live" ETI in any circumstance, but some editors are doing so if all tracks on a MB Release have the same ETI.  I don't think deleting live ETI is in the spirit or the letter of the guideline, so this needs clarification.  (Currently, the only kinds of "ETI" that the guidelines request to be deleted are "bonus track", "new song", and "The Beatles cover".  "live" is not included in the list of information to be deleted.)

If it is in fact the intent of the guideline not to delete "live" ETI in any circumstance, then I think a sentence needs to be appended to the above paragraph, since so many editors believe otherwise:

This ETI should be preserved even if all tracks on the release use the same ETI.