Hmmm... bang goes that theory then! 

I thought maybe there'd been a change to the default settings as I quite often click on the link in the email I get with the "matchmaker" settings or whatever it's called to chuck them a welcome message, as they must be brand new members, but I find no profile for them.

Maybe it's people disabling them on purpose, deciding they don't want to join after having a nose around? Doesn't account for those who disable their profiles yet still send nods though