It is rather easy to make a typo and create a new tag by mistake without even noticing it.1 Could we have a warning saying that the user is creating a new tag so that users can notice such mistakes more easily?
This was implemented a few years ago, see: Warning or confirmation on new tag creation.
As far as I can tell, this feature is not enabled on MathOverflow (or at least it was not in September). Could moderators request this from Stack Exchange staff also on this site (both main site and meta)? On Mathematics site, this feature exists since 2015: Warning for new tags.
Notice that this is different from warnings which are used for existing tags: Tag warnings on MO.
1It happened to me at least once. The posts How do I delete an accidentally created tag? and Delete the tag paperjs confirm that this occasionally happens to other users, too. I would guess that most likely the tags fa.functional and gfractals were also created by mistake. A few more examples: ag.algebraic-topology, asymtotics, represetnation-theory, a.g.algebraic, complex-gemetry, oc.optimization-contro, localy-trivial, nt.number-rheory, ac and ra, dicrete-geometry.