How did non-tech daughter wipe out Wifi Network?

Either my daughter was visited by tech savy aliens, or there was a HUGE glitch in Airport Extreme security. Yesterday, out ISP reported a problem in the system and we had no internet service for a few hours. I was away from home when service was restored. When I got home, I noticed my iPad had no wifi. I went to settings to check and discovered the wifi network name and password I set up two years ago, no longer existed. In its place, was a wifi password protected network named, "Jane Doe's Wifi Network" (substituting Jane Doe for my daughter's name). At first I thought she might be running a hotspot off of her iPhone. But with her iPhone in hand, Personal Hotspot was turned off. I won't go into details of our conversation, but suffice it to say, she had no clue why or how she had done this and gladly gave me the password for this new network. Because of Parental Controls, she has no administrative rights or access to System Preferences on her computer, which is named Her Name. Big hint there I thought. Is it possible after the Internet was restored, she was presented with a screen that asked her if she wanted to set up a new network (defaulting to the name of her computer) and assign it a password? Shudder.
Trying to resolve the issue from our iMac, I discovered that I was unable to delete this new network, our old network had all but vanished although the keychain password for it existed. I deleted the new network password from Keychain and attempted to remove it from the list of networks, but first had to ADD it to the list of networks. I then unchecked remember this network. Even then, this alien network named after my daughter continued to exist, and I could not recreate our old network no matter how many different ways I tried. I also got into the "this Airport has a personal IP address...." so tried doing all of the above again, as well as creating a new location. New / old network would never show up in the list of available networks. Now after midnight, I gave it up and began fresh this morning. I am now looking at my airport extreme setup guide to see how I can re-set it, hoping somewhere in the 41 pages of this 4"x4" manual I will find the solution.
But more importantly, I want to know how this could have happened. It scares the **** out of me that 1-if my daughter could stumble her way through this, anyone else could as well. 2-it will happen again.
Any advice, explanations or suggestions on how to proceed to fix this welcome. Daughter's computer MacBook Pro.


There are three possibilities here:
1) The Internet outage somehow reset the AirPort Extreme back to factory defaults. This is rare, but I have seen it happen. In that case, a screen would have appeared on any of the computers that were connected to the network...and there would have been a message that would have asked if the user wanted to re-configure the AirPort Extreme.
If this were the case, and your daughter was on the network at the time, AirPort Utility would have used your daughter's name as the default wireless network name and asked her to assign a wireless network password.
2) Your daughter discovered that AirPort Utility on her Mac allowed her access to the settings of the AirPort Extreme and she manually changed the name of the wireless network, also changing the wireless network password. Unless you have a separate "device" password and "wireless network" password, any user that is connected to the network can use AirPort Utility to change the settings on the device.
3) Your daughter held down the reset button on the back of the AirPort Extreme for 7-8 seconds, which would have reset the AirPort Extreme back to factory default settings, and she then set up a new wireless network on the AirPort Extreme.
As far as fixing things, you can use AirPort Utility to manually change the name of the wireless network and password back to the old settings, or change them to set up a new wireless network name and password.
If you are not sure how to do this, we'll need to know what operating system your Mac is using to provide the correct steps, since AirPort Utility has different interfaces depending on the operating system of the Mac.