Check each individual event for what is required for the dress code for that event. By everyone embracing their own interpretation of the dress code (in other words, a costume suitable for a faery or a woodland creature) yet within the lines drawn for the event, we create a more powerful and interesting environment.
This is how we create a communal event together and how is also part of how we show respect to each other. Because of that, if you are not properly attired, you will not be admitted to the event, regardless of whether you have purchased a ticket.
In general, the basic framework we are enjoying for the events is that it is part of the Woodland Faery Courts of Winter and Summer. Which means thematically that clothing and make-up and such should be inspired by faery themes or woodland themes. Which naturally includes all faery inspirations, woodland (and other types) of animals, trees (someday if I am very lucky, there will be an ent). Then dress it up or down or simply suitably for the type of event (a formal ball is different from a picnic which is different from a autumnal feast & hunt).