Bruh found a way to get free commercials and everyone acts like he was just that weird of a dude.
The Dunderdites got used to the camera and eventually acted natural.
But every time we saw Bob Vance (of Vance Refrigeration) was on screen, he was just showing up to plug his business. I think the one exception is the wedding, and he was a normal dude and pretty sure visibly angry about Michael and the cameras.
He didn't know the show would take off, but he heard thru Phyllis how crazy it was and knew the local community at least would watch it. That's all he cared about.