Compulsory voting
Countries that have compulsory voting by law but do not enforce it:Although voting in a country may be compulsory, penalties for failing to vote are not always strictly enforced. In Australia and Brazil, providing a legitimate reason for not voting (such as illness) is accepted. In Argentina, those who were ill on voting day are excused by requesting a doctor to prove their condition; those over away from their voting place are also excused by asking for a certificate at a police station near where they are. Belgian voters can vote in an embassy if they are abroad or can empower another voter to cast the vote in their name; the voter must give a "permission to vote" and carry a copy of the eID card and their own on the actual elections.
Referendums by country
Originally none of the Bundesländer (federated states) had provisions for a general binding referendum ("Volksentscheid" "people's decision"). Only Hesse and Bavaria have a mandatory binding referendum on changes to the state constitution. However, most states have a form of non-binding ballot question ("Volksbefragung" "people's inquiry") which has rarely been used - the most important one had been the Saar Statute referendum, 1955. General forms of direct democracy were first introduced in the communities with facultative ballot questions ("Bürgerbefragung" "citizens inquiry") and public initiatives ("Bürgerbegehren" "citizens request") that are both non-binding. In some areas, this has been expanded into a binding referendum type ("Bürgerentscheid" "citizens decision") but almost universally facultative. In some states, there is a general right on state popular initiatives ("Volksbegehren" "people's request") which was used in Hamburg to push the state government to pass a law on a facultative binding state referendum ("Volksentscheid") in 2007.