Many were complaining of “too many” Notifications because of the “now closed” posts.
My take is that it is not so important that every Moderator know that “this member has just been warned” when it happens, but that it is very important that Moderators know that “this member was warned about this before”.
i.e. as TechnoBear stated, the issue has been dealt with. But when and if the member repeats an offense, it may indicate a need for actions stronger than another initial warning.
Even without a “User Note” plugin, the “Warnings” indicator on a member’s Profile page could be of some use. Not as handy as a User Note, but at least it’s a “trail” of sorts