Your WAY off. Even the shittiest bag seeds will fucking STANK, Even in the Veg stage.
It really depends on how your exhausting the air in the grow area. If your exhausting out a window or something and you create a nice passive intake then it wont be so bad. But its gonna fucking stink man unless you run carbon filter.
All that water you feed your plants gets released into the air through Transpiration. Rub your fingers on the stalk of your plant, then smell your fingers, they will fucking STANK. You might not notice it so much when your there all day. But if you've been out for a while and you come home you will most definitely smell them if you dont have proper exhaust or odor control.