It feels that something like this should run on trust above all else. If I'm letting my neighbors borrow my stuff - or asking to borrow their stuff - I don't think I'd particularly want anonymity on either end. (Not the least because maybe I probably don't want to borrow a tool from Richie the Racist who lives down the block.)
Edit: I think I misread your comment originally, so I want to try again. At the moment, all the groups are invite only because that filtering needs to happen before someone joins a group, the platform isn't really meant to digest a stranger into a trusted community member, but instead enable existing communities, if that makes sense. I have the feeling that I will need to add features that platforms like Discord added to have people agree to rules, optional admin confirmation from people who use invite links, etc. But for now, invite links and QR codes are private. I hope this reply is a little better than the previous one!