I've turned back to stand twice after cabin crew gave a passenger several warnings (incl formal written warning) to stop using it. On one occasion I stopped on the taxiway, picked up the mic for a PA and stated quite clearly that 'we had stopped on the taxiway due to a passenger refusing to get of his mobile phone when asked several times by the cabin crew. Because this passenger seating in row x was still refusing we were about to return back to stand with a subsequent delay for us all.' As quick as lightning he backed down and switched it off within seconds and we left again. It showed a clear signal to all about who's in charge... (c/c) We got an applause from lots of pax...
That was in the UK. Now in the Middle East and you can just as well forget all rules...
It's a different mentality here.