My poor Ivan.... I hope his futur clients don't read Tattle and your excellent message!
You have good heart, you give a good excuse to our arbiter of elegance caught in full act of ignorance, haha! But Covid is never an excuse in the good society because a woman accustomed to thoses places knows how to dress before living the house/hotel. She knows if she will be annoyed by her coat or jacket or shoes or umbrella or bag (or husband if she has a lover waiting for her) and she knows how to find a solution. I have the solution(s) but let's not make her life easier. This woman knows as much about Opera (music, behaviour, rituals) as I know about the nuclear fission, yet I live in the region where the CERN is.
Everywhere in the Western world is the same and it's very sad. I would do an exception for the MET. The last time*** I was in a big Opera House, with a very good representation of La Traviata, was in January 2020 at the MET, just before the Covid. It was a "matinée" (for those who don't know: the representation starts around 15h), and I only saw people well dressed, especially women around 50, 60 or 70 years old from the good NY & American society. But I think it was an exception because it was the big week of auctions in NY and the big dinner of Old Master Drawings Society where everyone with a pedigree in art and finances in America was invited, it was a special week for New York. I was also in the first good rows in the front, I wasn't able to observe the boxes and the balconies, as you all know the MET is huge.
Anyway, what I wanted to say is the following : being well dressed and groomed in a theater or in an Opera House it's a courtesy for the artists. The post-1968 mentality, which eventually led to our today casual look, confused the fight against the symbols of the bourgeoisie and the courtesy to the artists. Every artist outhere will tell you that they play better when the auditorium is full and people have made an effort in their clothing, as if they wanted to celebrate the artists, like in a feast.
Since I am here : another thing to avoid, especially for Opera. I saw this rude faux-pas everywhere and it's very ungracious for the artists : always stay for the applause, never leave your seat when people applaud, even if it's late and you have a bus/taxi/train to catch. Usually people do this, especially women, because they want to be the first to take back their coats at the cloakroom. It's very mannerless.
*** Actually the last one was "Les Huguenots" in Geneva but it was just before the first lockdown and the rule was 1 seat/2, so it was half empty and very sad.