Where/when local community had discussed it?

>  And yes, if say Vilnius would be left without any inhabitants but would be left as capital in our constitution then yes it would still be place=city.

That would actually make sense (and would happen only during some major war/catastrophe and mapping - of possible - would happen afterward, not during it)

I am thinking here about case of government declaring empty unimportant field as city (as legal loophole or for other weird reasons).

Would it then be mapped as place=city? I think that it would be a clear mistake and you seem claiming that it should be actually tagged as a city solely because government classified it as a city.

> If anybody wants to classify places by population

This does not really work either as there is no direct clear mapping

> We tag places according to CARTOGRAPHIC requirements

And common cartographic requirement is to have place=* reflecting reality, not government classification - and it is supposed to be used for that.

That does not block putting government classification into some other tag.