It depends a lot on the strain, and also how big you allow your mother to grow. I had a mother plant that I kept in my master closet for a while, and while it was just a few feet tall it wasn't any issue. Once it grew for a few months and got bushy as hell, I started noticing that the clothes I was keeping on the other side of the closet began taking on a pretty distinctive smell! Certainly not as bad as a flowering plant, but noticeable nonetheless. Again, I think it also heavily dependent on the strain.