If you are using Apple TV 3 Rev A then it is likely because they use Bluetooth to "help" Apple devices find the Apple TV and then they establish a peer to peer Wi-Fi network to facilitate Airplay.

One way to prevent them from being able to Airplay is to put a passcode on the Apple TV for Airplay and distribute the passcode as a profile from Casper or email the appropriate people the passcode.

If it is distributed by Casper the client will not be prompted to enter a passcode however if you email out the passcode then the first time a client tries to connect then they will be required to enter the passcode. This will establish a trust between the client device and the Apple TV. The client will not be asked for the passcode again for that specific Apple TV.

Please be aware there is a known issue with OS X clients. Should be fine for iOS however.

[D-008152] End users are incorrectly prompted for an Airplay password when attempting to Airplay to a device for which an AirPlay password has been specified using an OS X configuration profile.

Cheers,
Pat

@PatrickD Thank you so much. I don't know why it is showing up on the main network. I still have the separate network for the Apple TV so it is an uninterrupted WiFi signal. I have the WiFi passcode and Apple TV airplay passcode in all one configuration so users can just install it on their device.

Thanks for all the help,
Jared :)

Try disabling bluetooth on the Apple TV.