Wear what you like, but without a badge around your neck, you are nobody. It's your ID, your meal ticket, your means of entry into sessions and talks. It's your access card to the WEF intranet terminals, where you can send messages to other attendees. It is also a social pheromone, the color a signal as to the social desirability and usefulness of the person. So, here's a primer on the Davos class system.
P is for peon.
The purple badge represents the essential but ignored people, like support staff for sponsor companies or tech troubleshooters. You trail behind your illustrious superior, tending to his or her whims and helping to identify undesirable badge- wearers. There are in fact degrees of blue-ness. So far, we've discovered two. Pale blue means junior WEF servitude.