I fell for it once a couple years ago, and its even more embarrassing since I had already been working in the industry for like nine years.
I don't really want to go into too much detail, but I had to talk to an HR person because of some "concerns" they had about me. The concerns were actually perfectly fair, and the HR rep was very friendly, but when I explained some personal information to the HR person in response, and despite the fact that I told them it was something I wasn't terribly comfortable telling anyone, they felt it prudent to tell my direct manager, and his manager, and his manager's manager that day.
I wasn't at the company much longer, but that wasn't even the reason why.
Friendliness goes a long way towards quelling suspicion. I think it's rather safe to say unassuming kindness can disarm most anyone who isn't a cutthroat, Type A personality.
I'm autistic as hell and I can still see how people would fall for it.
