I can see where you are coming from. I am like you. If I want a small, intimate shower with only close family and friends, then I would hope the hosts would oblidge my wishes.
My mom has done this and after going through a few showers, I just don't appreciate having my mom's friends, who I hardly ever see, there. Looking back, I wish I would have asked the hosts to stick to the guest list and not let my mom invite anyone extra.
I also wanted to add that I don't particularily enjoy my mom's friends company either. That could be why, in hindsight, I wish they were not invited.