If you've signed out, the product is unusable and is deactivated. If you try to use it, it will ask you to sign in before it will allow you to use it.
What makes you think it has not been deactivated?
My other PC keeps saying it needs to be deactivated on another PC. You see, I had to get another motherboard put in my PC, so it thinks its on a PC that's its not, the one I'm using and the one I deactivated it from.