IT handed me a faraday bag for my phone before my business trip. Why can I not just use airplane mode?Solved

Airplane mode only does half the job, which is exactly why corporate IT departments do not trust it for international travel. 

A faraday bag is basically a portable shield made of special metallic fabrics. When you put a device inside and seal it, those materials absorb and distribute electromagnetic signals, completely blocking anything from getting in or out. 

The problem with just turning off your phone or using airplane mode is that a compromised phone can fake being powered down while still transmitting your location and data in the background. Plus, airplane mode does not always stop Bluetooth or hidden tracking pings. The bag guarantees absolute radio silence so nobody can intercept your data while you are walking through a busy airport. 

The absolute radio silence @noah-blake mentioned is crucial because the threat you face in certain regions is literal corporate espionage. 

Hackers and data thieves set up fake cell towers or malicious wifi hotspots in hotels and transit hubs specifically to target business travelers. If your phone is just sitting in your pocket on airplane mode, someone brushing past you with a concealed scanner might still try to ping your device to steal credentials or install malware. 

Keeping the phone in that pouch means your device literally ceases to exist on any network until you are in a safe room and choose to take it out. Just make sure you fold the top of the pouch exactly how IT showed you, because even a tiny gap in the seal will let signals leak through and defeat the whole purpose.