If bbpress is running on a subdomain, then it seems to be adding network users who visit the sub site to the sub site's users as participants - this includes the super-admin! Any idea how to stop this?
Under the Main Settings for Forums, everything is checked apart from:
Anonymous posting Allow guest users without accounts to create topics and replies
Auto role Automatically assign default role to new, registered users upon visiting the site.
(which are unchecked! And these have not been touched as they are the defaults.)