The period police are saying they will not going to allow people with ears, vampire teeth and punk hair into Birka. The guide lines will be if you do not show you have made an attempt to be period then the period police will be coming for you. So with that, consider if you show up with with fox tails, devil horns, biker boots or black sneakers you are a bad boy, what you going to do.....the grab police are coming for you. I'm sorry this is so sad I have to joke about it. But seriously, this is not a joke, they are sadly serious.
BTW, there will be reminders flashing on their laptops to throw anyone out that is not period in their thinking....ok I made that part up.