They would first be admonished and repentence would need to be displayed. If not, they would be "marked." If they persisted in their behavior they would be df'd. They don't pursue this topic as idolatry as far as I know, but in conformity and quality of association and influence on others.
Birthdays, and just about anything else not clearly defined, can also be covered by "Loose Conduct." See the interesting chart that follows.