I watched in amazement on a domestic flight (in Australia) as a fellow passenger took a call mid flight - spoke to the person at the other end in chinese, and looked shocked when a member of the cabin crew told her to terminate the call.
(Australian Federal Police were waiting to have a word or two wuth the passenger when we arrived in Sydney)
I can see one day some passenger demanding to open door 1L for some fresh air at FL380.
No matter how cheap and safe, there are always wingers.