How do I prevent people from shutting down my samsung phone? When I have the passcode enabled, you can still shut down my phone when you press the power button. Is there any way to prevent people from shutting down my phone?
You can't do it 100%, because it is, like mentioned by bmdixon and in here 
How to prevent someone from powering off an android device?, a hard-wired feature. But you can get rid of the on-screen-option with this App: Smart Lockscreen protector (Play Store)