"I ever wanted to start an industrial espionage company, I'd use secretaries. They had access to all kinds of stuff"
Yes. Yes. YES!!!
I wuz gonna point that ~OUTT in my post about desk drawer pads and fileroom/server access.
And it is why you always have to be very careful about who you hire as a secretary, IT person, fileclerk, etc. - because ONE weak link defeats the whole system.
It can be through negligence, of because they are paid to provide information - or in some cases because they are PLANTED as secretaries, EAs, IT personnel, etc. That's why HR departments need to do deep background Czechs and you need to be very thorough in interviews with people. And avoid hiring people with bad credit, a criminal history, or who have worked at a competitor/competitor of a client/or has a close relative who works for one now.
It can be tough to get these answers because you're nott allowed to ask potential employees about their relationships, etc. like 'are you married?' 'what does your spouse do for a living?' etc.
So you have to do deep internet and database diligence on potential hires. Who lives at their address? Where do those people work? Parents? Kids? Kids work where? Parents work where? Facebook is a great aid in this for most people.