Nosey spouse? NSA tracking you? Just want to made sure you are not "available"?
If for some reason you want make certain your phone (or a visitors phone) is "blind" to location tracking, showing that iMessages are delivered, confirmation emails, GPS, etc. place the phone in a microwave oven.
Here we use a Tektronix RSA306 Real Time Spectrum Analyzer (which is located behind the PC screen) to demonstrate the effectiveness of a microwave oven as a RF screen room. Notice the RSA306 can "see" WIFI/Bluetooth signals when the door is open. When the door is closed anything inside the oven is "blinded" to all cell phone communications. All of them.
If you want to hide your phone (or hide someone else's) from all network communications, put it inside a microwave oven.
Oh, and don't turn on the microwave with your phone inside!