Anywhere that users upload public keys for cload access we should have a warning says something about not re-using a public key for the cloud, or not reusing a key that's used basically anywhere else maybe.
An example of where this should show up is:
There's a similar place in Striker.
You can use the "qqx trick" (TLDR: append ?uselang=qqx or &uselang=qqx to any wiki URL) to find the existing MW UI message-strings, which can potentially be overridden. (Note: that only works for one-language at a time, so this method is cautioned against on our other wikis, but the vast majority of our devs are bi-lingual in (and I assume using Wikitech in) English.)
I.e. https://wikitech.wikimedia.org/w/index.php?title=Special:NovaKey&returnto=Special%3APreferences%23mw-prefsection-openstack&uselang=qqx leads us to the string MediaWiki:Openstackmanager-novapublickey. You could add anything there.
(or you could update the original en.json to enable translations - there are 47 existing translations, despite the extension only (?) being used on wikitech!)
#probably_all_known,but_maybe_useful_to_someone! #needs_an_acronym
Yep. Or, moreso -- it can just say "don't use a key here that you've used anywhere else"