She definetely saw, and i think it would stand out to her even if she never seen it before in her life. its a unique plant. It stood out to people thousands of years ago, before anyone knew what it would do. if she was upset enough to tell anyone, it would be noticable. She would act differently if she thought she was in the home of "criminals". ya dig?
Although your right, thousands of years ago, when people didn't know what it could do, it wasn't noticeable to them.
If I was that lady that came to see his house, and I "double looked" at a plant I saw in the back yard, it'd probably be mostly because of how it was placed, or if it just stood out from the rest, such as being left in pots, or planted in somewhat in sight.
If she doesn't know what marijuana looks like, she can't say "Oh, I know what that is", or anything on the sort. Heck, first time my mum ever came into my room when I had my first grow, and she looked into be growing box, she kept looking at it profuseveily, as in doing like Sims (Ooo-aaa-ing the plants, as if they were pets). I just told her I'd gone over to the closest plant greenhouse/store/thingy and bought a plant of peppermint.
(It was still in it's early sprout stage, so it was a reasonable "camouflage".) And since peppermint has very similar leaves, it wasn't too hard to convince her.
So yeah, not because someone looks twice at something that she recognized it. Unless she acted weirdly AFTER the double-look, there's no indication she had any trouble, or any realisation of what it was.