Turn it off, lived many years without phone/tablet...can certainly survive without them for a couple of hours

That battle is lost anyway imo. On every flight i see 1-2 people from my seat who are still using their phone/tablet or simply put it away (but don't turn it off).

Also the counter for seeing crew using it this year stands at 3.
1x KLM cabin crew using whatsapp untill accelerating on the Schiphol runway and 2x DL crew on AMS-MSP legs. On one occasion the purser made a remark to the DL FA: be carefull they (pax) might see it....eeeuh Mrs. Purser and FA, i give you a hint: when sitting in 1B/C on a A330-300 pax indeed can hear what you say and see it lol....