How to disable installing from unknown sources? Is there a way to disable the phone from installing apps from unknown sources?
I know that it is possible by just going to.  

settings-&gt;security-&gt;unchceck "unknown resources"



But when kids install apps, a dialog appears:



By just tapping on settings, they can Enable it again and install the application.

is there a way to disable it and the dialog won't come out or make it grey so it won't be clicked/tap it again? Without putting password on my Settings.
If you have Android OS Lollipop and above, you should create a guest mode for anyone you wish to hand over your cell phone, you can define the rights in the guest mode.