> If they're relying purely on a land-based mobile system to get them out
> of said "life and death situation", they can't exactly be "serious
> 4WDrivers", can they...

Good point, actually. The bare minimum comms for 4wd would be UHF and HF
radios, and for those with a fair dinkum bank account, a sat phone, (if
there is one at the time). A mobile phone is next to useless out back.