Let me start this again, maybe I wasn't clear about my issue. In Settings, WiFi I have the "Ask to Join Network" is enabled.
Every once in a while my iPhone will connect to one of the various other another WiFi networks in my neighborhood without asking me if I want to join it. Then I have to click that network and press "Forget this Network" and join my home WiFi network again. Shouldn't I be getting some sort of prompt about joining a network other than the one I set my iPhone up with? If I turned "Ask to Join Networks" off, then I could understand it doing this.