Turning of GPS doesn't exactly make you hidden location wise anyway, all it takes is 3 cell towers and the exact time it takes packets from each of them to get to and back to them from your phone and a simple piece of software to run those packet times through and they have your location to within a few feet...

if you want to hide, physically turn of your phone and put in a faraday cage/bag(leaving it on will drain your battery in no time through the phone constantly trying to connect to a network it can't get to), hell a few wraps of alu-foil or rolling it up in an empty chips-bag(mylar with metalized inside) would give near 100% guaranteed signal blockage, a metal can with a metal lid with a good seal(overlap joint rather than a typical paint-can seal)would also be likely to work.

Turning of GPS doesn't exactly make you hidden location wise anyway, all it takes is 3 cell towers and the exact time it takes packets from each of them to get to and back to them from your phone and a simple piece of software to run those packet times through and they have your location to within a few feet...

if you want to hide, physically turn of your phone and put in a faraday cage/bag(leaving it on will drain your battery in no time through the phone constantly trying to connect to a network it can't get to), hell a few wraps of alufoil or ruling it up in an empty chips-bag(mylar with metalized inside) would give near 100% guaranteed signal blockage, a metal can with a metal lid with a good seal(overlap joint rather than a typical paint-can seal)would also be likely to work.