They are at least for nonEU ppl. Friend got in big trouble because border agents didn't stamp her passport - she went to the us, got an exit stamp but no entry

They are at least for nonEU ppl. Friend got in big trouble because border agents didn't stamp her passport - she went to the us, got an exit stamp but no entry or exit stamp from us and no entry stamp in eu (lots of ppl got lazy...). A routine visit to immigration office suddenly turned into pretty strict questioning and several hours of waiting until they check her passport.