airportSecuritysettingswifi
How can I prevent OS X (and ideally iOS devices as well) from connecting to a WiFi network which has the same name as one of my preferred networks, but isn't the same network?
For example say my favorite coffee shop has an open WiFi network named "Free WiFi" and that's fine, but so does neighbor who runs a proxy which changes all the images sent over HTTP to pictures of butts… hilarious… but[t] annoying.
If you have checked both the user keychain and the system keychain for old passwords, we're left with obscure guesses.
Two things come immediately to mind (from the obscure side).
Open System Preferences, go to networks, select Airport and make sure the "Ask to join new networks" check is not selected.
This will suppress the dialog all the time as there isn't an easy way to have it suppress a second dialog in a timeframe or after a disconnect event.
Best Answer
Obviously you joined neighbors network once upon a time.
Since you have the "Remember networks this computer has joined" Enabled, it will remember it.
Find it and delete it in networks - advanced, or just delete both and next time reconnect in the coffee shop, but do not connect to Free WiFi if showing up when at home.
The fact that they have the same name showing "Free WiFi" is only for us humans, the computer use BSSID to identify the stations.