The difference with my mom is that her allergy to weed is bad enough that being around someone who recently blazed could send her into Anaphylactic Shock within seconds.
When I got stoned all the time I always carried extra clothes in my car and showered at friends houses before going home. Her brother for the longest time that I knew
wouldn't allow her in his apartment/home if he had been smoking because she came in to visit once and got hospitalized because he had so much smoke in the air. I can
definitely understand where you are coming from though.