My mom stopped by a few weeks ago and was in the room with Blue Cheese 4 weeks into flower for about 5 minutes and didn't notice. I am sure from childhood that she knows the smell and would have bitched at me too. My chick's parents were here for a few hours when they were a bit further along, but I don't know how familiar they are with the smell. Close to harvest I can catch a faint whiff myself if I'm in the same room.
Carbon works pretty good, but if you're like me and enjoy watching the plants frequently then the smell just works its way around the house. Gotta keep them closed up for a few hours at least to let the lingering scent dissipate.