Another one here for everyone I know is voting IN including all my colleagues, friends and family. Does seem to be one or the other.
Same here - I've not met a single person who says they will vote to leave: at work, socially or among relatives. All say they will vote for IN.
I suppose, though, that there's a real possibility that some people are embarrassed to identify themselves with the OUT camp (because of its association with UKIP, being against migration etc). Similarly, I've hardly ever met anyone who's admitted to voting Tory, but there a lot of them out there, so again it could be an embarrassment factor.