Is the ‘Balmoral test’ compatible with the rules of hospitality?

According to the Netflix series The Crown, there is an informal ‘Balmoral test’ which guests of the Royal family, when invited at their Scottish country house, are expected to pass. This ‘test’ is a lot about wearing the right clothes, enjoying the right activities and doing the right things in different particular situations.

Apparently, the then prime minister Margaret Thatcher, by joining the hosts at 6 pm dressed up for dinner while everyone else was dressed informally for the drinks, has dramatically failed the ‘test’. While Mrs. Thatcher’s ‘failure’ is probable (after all she came from a different background: less privileged and more free-market oriented), it is quite unlikely that she failed it in that way.

British newspapers are currently filled with quiz-articles asking readers if they would pass the ‘Balmoral test’.

A ‘Balmoral test’ surely exists in one form or another, and not only in the Scottish residence of the Queen. Most importantly, it exists in the minds and even in the instincts of many individuals. And I venture to say that the more elevated individuals are in their own field (whether it is aristocratic background or bitcoin expertise; alpinism or sailing; etc.) the more they will tend to impose the ‘Balmoral test’ on their guests.

But is this test (or rather its more or less explicit disclosure to the guest) compatible with the rules of hospitality?

First of all, what kind of rules are these?