As I explored my new Nexus 7 using the built in manual I got trapped in TalkBack. Once started there is virtually no means of escape. I spent almost an hour trying to exit the application including several attempts to reboot the tablet, each time it came back to life still stuck in the TalkBack mode. I was on the point of doing a factory hard reset when I (with help from several colleagues) figured out a way to "Double Tap" through several screens to return to the settings screen and turn off the TalkBack. The experience was not fun and very frustrating being stuck in an app that I was just dabbling in.
Beware of Apps with unintended consequences.
Beware of Apps with unintended consequences.