In Greece a course named “religion” is not an optional one. A course mainly focused on orthodox-christian beliefs using manuals aimed to inform about christian god and traditions is compulsory and everyone must attend. Attending an orthodox-christian morning prayer is compulsory as well.
In order not to attend the above, one must provide the school with a written permission by one's parents in which one's beliefs are declared as non- christian ones.
Religious freedom involves the right not to declare a belief. Apart from declaring students are asked to have their parents' written permission not to attend a course aimed to teach only one religion's views on religious issues.
I consider school students to be individuals having their essential individual rights protected by the constitution. Thus they do not need permission for exercising them. Religion courses must be optional, while compulsory morning prayer has no place in a liberal democracy.