|You could easily limit what time of the day they can use it, but if they're old enough and/or computer savy enough they may figure out how to disable this or get around it.|
Control Panel - Printers and Faxes - RIGHT click on the icon for the printer - Properties - Advanced
Click on the blank circle beside Available from:
to insert the dot.
Choose a time range other than 12 AM to 12 AM, or any time to the same time (if both entries are the same the setting is automatically set back to the default - Always Available).
Click on OK.
You may need to reboot after changing the setting in order for it to take effect.
Change it back to the default - Always Available -when you're there and need to use it, or need to over-ride that time range for them, if necessary.