I think it's got to be mostly about what makes you feel most comfortable with yourself and your faith. For me, I would tend to think sharing ritual community and positive commandments would trump the letter of the law - and I'd even debate to a degree whether Folk Fest is "work of the week", being a volunteer thing you do primarily for the good of others.

In the end, I'd prefer to think that a supreme deity would be more in favor of outreach, connection, and good works than a stickler for rules designed to call to mind His own reverence, and that's the world I'd choose to live in. Of course, IANAJ, I'm an outright dirty heathen. Thus, take all this with a grain of (kosher?) salt.