In the airline i work for, we do not let pax use mobile phones at all. Despite announcements being made to tell them this, some people still break the rules. Many a time when boarding or disembarking pax turn on the phones and try to use their phones on the ramp, this is not allowed either. It even tells you in your mobile phone handbook that your phone must be switched off prior to boarding an aircraft.
Hope this clears this matter up for you.