[c_o_n_v_e_x]

It's been a while but I can remember going to sport events where the local cell network could not cope with the traffic. Calls wouldn't connect and SMS were delayed.

These would also be handy in construction when you're deep in the bowels of a new building and can't get any reception whatsoever (cell, CB, etc.)

[Hugsun]

These are the scenarios I was looking for. Thank you.

The extreme event scenarios have pretty obvious applications but are also very rare.