I recently purchased an iPad for my daughter and for whatever reason, it came with VoiceOver on. Unfortunately, I could not find a way to disable it before going through the initial configuration of the device. As a result, the initial configuration took a long time. Once I made it through the configuration and disabled VoiceOver, I finished configuration and gave the iPad to my daughter for her birthday. Somehow, she kept turning on VoiceOver. After some research online, I came across a post that explained the issue and how to fix it.
As it turns out, VoiceOver appears to be mapped to the triple-click home button — if you select the home button three times rapidly, VoiceOver turns off. You can repeat the triple-click to turn VoiceOver off. This configuration can be changed under General > Accessibility > Accessibility Shortcut. You can read this post for more information.