When creating a new world and don't allow cheats cheating without a mod is impossible until you don't open the world to LAN and allow cheats. 

It makes Minecraft on singleplayer survival mode is almost unplayable in my opinion because when you die for example, you click on the Open to Lan option and allow cheats, you type in chat /gamemode creative and get your items back. After 1 minute you realize that survival is pointless. Removing Open to LAN button or allow to cheats (after selecting Open to Lan) will be the best option in my opinion and survival mode on singleplayer be finally playable.