Creon's decree to leave Polyneices unburied in itself makes a bold statement about what it means to be a citizen, and what constitutes abdication of citizenship. It was the firmly kept custom of the Greeks that each city was responsible for the burial of its citizens. Herodotus discussed how members of each city would collect their own dead after a large battle to bury them.  In Antigone , it is therefore natural that the people of Thebes did not bury the Argives, but very striking that Creon prohibited the burial of Polyneices. Since he is a citizen of Thebes, it would have been natural for the Thebans to bury him. Creon is telling his people that Polyneices has distanced himself from them, and that they are prohibited from treating him as a fellow-citizen and burying him as is the custom for citizens.
And she's far from the only person who has courageously placed morals over state laws.
Remember history class? You have lots of modern examples of people who have chosen to fight for justice rather than preserve their own safety. Consider Dr. Martin Luther King, Jr. or Gandhi , both advocates of civil disobedience and peaceful demonstrations, who were assassinated as a result of their fights against oppression. Or think about Nelson Mandela , who risked years in jail to stand up against the apartheid government in South Africa.
Antigone chooses to express her dissatisfaction with what she believes to be the unethical new regime of King Creon by burying her brother's body. She resolves to sacrifice her own life in the service of a greater justice. It's this kind of almost superhuman resolve that changes the course of history—and that's something that we can admire equally in the 5th Century . and the 21st Century .