As I see it accepting hugs and keep your distance are competing social norms.

Usually it is assumed that keep your distance applies unless among close friends. Someone wanting to use hugs as a form of greeting would have to take the initiative, break the dominant social norm and ‘impose’ a hug on the other person. The opposite case of a society where accepting hugs is the norm would also be a stable state for similar reasons.

By providing stickers for signaling a preference for one of the two opposing social norms we (one of the organizers writing) wanted to provide space for both of them. The problem here was the wide adoption of hugs welcome that lead to people assuming it without consciously checking the tags. A stronger color difference might have helped here and we actually had considered printing the keep your distance stickers in warning colors. We decided against that to avoid giving it the feeling of something dangerous or negative and frankly: We expected something like 7:3 and not 9:1.

Naturally everybody will prefer a different point on scale of social contact and society has to provide a compromise. The strong adoption of accepting hugs shows that the usually dominant social norm is - at least in the context of a community weekend - not aligned with the interest of the majority  of participants.