Yandex is an interesting showcase of how bad this can get - they literally dropped country borders from their maps last year "for better user experience". And I don't mean just lines that you normally see while browsing the map, but even when you ask for it deliberately. For example, if you look up a city, you get its territory highlighted on the map - but that's not the case for countries, it just puts a marker "somewhere in the middle".

They also removed administrative regional boundaries without announcing that change - probably because looking up regions at the border would have to include a part of said border into the displayed boundary, making it discoverable.