This is pre-pandemic and very typical.Just chanced upon a couple of recent milongas in BsAs on YouTube. One outside, but sparse, and a few dancers wearing a mask; one inside, again sparse, but more dancers wearing a mask (some not well). Very different situation, and an unrepresentative sample, but still interesting.
There's always one of more though - see at 45 seconds onwards.
This is the Buenos Aires solution to social dancing,
dancers breathe past each other and the woman
is able to act as rearview lookout. Similar does happen
in social ballroom although the form is different.
Agreed it takes just one but unfortunately now you can expect more.But it just takes one. I can wait a few weeks until we know the impact of Omicron.
And the offender can just be careless, thinking they have never been
infected, but now unknowingly infected, skipping the actual test
in haste or ignorance but reporting negative anyway. Stringent
precautions, testing on entrance for instance (I know, not logistically
possible really) verifying Covid Vaccine passes by scanning etc., etc.