Unless your cell phone is powered off with the battery and any external power supplies removed, or it is locked inside a Faraday cage, anyone can do it.
Or even a readily available Faraday Bag, via Prime no less:
✅ Do not compromise your shielding with knock-off bags! The only authorized Amazon seller comes from the name "MOS Equipment." Military-grade faraday bag designed for law enforcement forensic investigators.
✅ Shields cell phones, GPS units, electronic toll collection transponders (like E-ZPass), keyfobs, or other similar size devices from ALL wireless signals. EMI shielding & RFI shielding. Two layers of high-shielding fabric on all sides with dual paired seam construction. Used for forensics, military, executive travel, personal security, EMP protection, and solar flare protection.
✅ 100% shielding of WiFi (2.4 & 5GHz), Bluetooth, cell signals (4G LTE+), GPS, RFID, and radio signals with 60-80dB average attenuation.