Obviously when travelling by public transport, all I need to cross non-EU Balkan borders (meaning Albania, Bosnia, Kosovo, Macedonia, Montenegro and Serbia) is my identity card.
However, what if I were to rent a car in Switzerland and wish to drive to these countries? What exactly are the "basic" things to show at passport control besides the ID?
From what I know, it's just the rental contract. If that's the case, is it always asked for along with the ID, or only occasionally?