Do people who smell know they smell?

I work in retail and all day long I have people that come in and just absolutely reek! It is disgusting. Sometimes the stench will linger long after they have left resulting in me dousing the store with air freshenser. BO smells, musty smells and this smell that I can't even explain which I've smelt on several people. Do these people know they smell like a$s and just not care or do you think they're oblivious to it. If you yourself are a stinky one, please tell me where you get off thinking it's okay to expose people to your poor hygiene? Shalom.