Yeah and they actually have interacted with the crew before, although the crew wasn't on camera. In the episode where Pam starts suspecting Dwight and Angela the camera guy comes running up to Pam to show her Dwight eating that candy bar.
Personally I don't have a problem with the Brian storyline because it doesn't make sense for the crew to suddenly interact like that, I have a problem with it because the storyline sucks.
I have a problem with the casting. He's just a bad actor and looks like a creepy model. I wish he looked more normal. I don't mind the storyline because Jim and Pam have always been annoyingly perfect. So perfect it felt forced and unnatural. That's always stuck out to me.
It's also a little weird that in nine years Brian hasn't graduated from boom mic operator. Is that normal?