Spring/Jack
Usually 'registers users' are people who earn 100k per annum. Unfortunately I do. This was confirmed (as with me years ago) via a questioner e-mail when joining the site.
Mixture....."Dunno. PPRuNe is a bit weird, it runs on vBulletin software but they've hacked together all sorts of custom tweaks over the years. This might be one of them"
I fear a good spanking may be needed.