Full disclosure: The info and images below are pasted from an ASHA Community SIG 12 discussion via Bruce Engholm of Kingston, NY, originally retrieved from http://www.imore.com/how-use-guided-access-put-your-ipad-or-iphone-guest-user-mode Thanks Bruce!
How to turn on Guided Access
Be aware - this fantastic addition to iOS occasionally works too well!
At times, the required triple click of the Home button, while in Guided Access, does not do anything, and then you're really stuck in the app. This leaves you unable to leave Guided Access mode, but here’s a workaround to get out of it until the bug is resolved:
- Hold the Home and Power button together for 15 seconds until a reboot is forced on the iPad, iPhone, or iPod touch
- With the device rebooted, go back to Settings > Accessibility > Guided Access > and turn OFF as necessary
The stuck app bug doesn’t appear to impact any native Apple apps, but it does affect many popular third party apps. Expect a resolution soon that doesn’t involve rebooting with iOS 6.0.1 or a similar incremental update.