Not owning, nor having a reason to use a cell phone, I find this article amusing.
If you do not want to be tracked and scanned and monitored, your cell phone’s best friend should be a mylar potato chips bag.
One Faraday Cage, coming up!
Any metal enclosure/box/bag will work fine - turn it off first else the battery will run down in Roaming mode.
Bury it (deep) and it becomes an EMP shield.