There are some question which are related to this,. but getting the exact answer:
Lock-down iPhone/iPod/iPad so it can only run one app
Recently iOS 6 is introdu
Hi may be I am late but I have a good news for you.
Apple provide a new feature in IOS 7 and we can lock the user to single mode without user permission(Lock and unlock mode) here is the apple documentation link
https://developer.apple.com/library/ios/documentation/UIKit/Reference/UIKitFunctionReference/#//apple_ref/c/func/UIAccessibilityRequestGuidedAccessSession
the other way is to install the profile config profile like is
http://ipadhire.co.nz/lockdown.mobileconfig
it lock the home button of IPhone and enable single mode