I'm on a school network so I have to sign in before I can use the internet. Before in OS X 10.6 it would just connect me to the network and let me signin on my own. Which I made a script to login for me.) However, now with this new join dialog that pops up asking with the login window, I can't have my script automatically log me in.
So how can I prevent OS X Lion from attempting to join the network? I looked into this and it works like on the iPhone. The computer will try to access http://www.apple.com/library/test/success.html and when that fails it will show a pop up window asking for my login.