Or maybe you can play games with a friend on the plane through the wifi link?

And yes, it is easy to turn off the link on all machines - it needs to be this way as often you don't want the link to be on.

Sometimes having the link on gives you a pleasant surprise. I recently was at a hotel in DC and my computer found a live internet link. I was not looking for it, but I turned on my machine and there it was! Either some local business had an unprotected wireless router or the hotel was experimenting with unpublished wireless access.