Easy to do.
Lets use GCHQ as an example.
Been there know what they are about. I knew quite a few workers and ex workers. One of my best friends worked there, they know who I am as a real person, I am not a risk, (he had been reported due to a prank and I was mentioned, demonstarting his electronics skills). Lets just say I have a video tape of me standing on a gate holding a TV aerial pointing at my home, and the tape never left my home.
Now at work we recently took on a Pakastani chap, he knows a few dodgyish people just by being from there.
Now would that be considered a risk?
Here no - none whatsoever.