You're implying the stub of an exposed coax inside a faraday cage is capable of establishing a link with cell towers. This doesn't really pass fermi tests and I've never observed it myself, just read the paranoid concerns of people online.

Regardless, taping some foil around the connectors with the foil making okay contact with the metal chassis is more than enough attenuation at sub GHz microwave to remove this concern without having to source specialty terminations and crimpers (or worse, non-reversible damage to the OEM cable assemblies by repurposing their terminations). I've done the foil+tape on some of my vehicles, but it hasn't made a difference in binary "does it connect or not?" testing.