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.
Elections in Greece
Compulsory voting is the law in Greece but is not enforced. In the past a citizen had to present an up-to-date election booklet in order to be issued a driver licence or a passport, or else justify why they did not vote (e.g. because of absence, infirmity, or advanced old age). Nowadays the civic duty of voting is still considered "mandatory" but there are no sanctions for failing to vote. Turnout is usually high, typically between 70 and 80% for legislative elections and slightly lower for local administrative and European Parliament ones.