I often check my worlds to see if people are in them on the VRChat website, the site will tell me that there are people in a "Public" instance, and that I can click the instance to join them, but surprise surprise, I CAN'T join them, because only members of that group can see the instance, Group Plus instances are pretty much just slightly less strict Private instances, I don't understand why they would be listed as Public if the majority of players can't join them, I think they should either be listed as Private or get their own proper label.