Your Safety is Compromised if You’re an Intervener
If you feel compelled to do something about someone 'breaking the rules' you may want to consider why it's so important for others to follow them.
Primarily, if you find yourself wanting to intervene and play Sherriff you may find yourself in a compromising position if the person you are trying to 'control' verbally doesn't take kindly to your efforts.
There are all manner of mental issues humans are dealing with as well as the very situation where altitude effects an individuals judgement. A good natured person could turn on you in a delusional state if are trying to get them to what YOU want them to do and take your non-confrontational efforts as very confrontational. Reality is a subjective business and we all perceive moments in time the way we as individuals perceive it.
If you would up in a confrontation with another passenger on an airline you could find yourself in jail even though you did nothing wrong because, again, your actions will be perceived from the outside looking in and it's subjective to the viewer.
Reality Check
Imagine a scenario where you are landing in Malaysia or Singapore and your punishment for 'being aggressive' and 'disrupting an International flight' has corporal punishment associated with it. Add to that the state of prison systems in some 2nd and 3rd world countries and the potentially horrible experience you could have because of misperception from others over a cel phone issue and you can play out a very dark storyline.
I only say this because people are incorrectly perceived all day, every day, around the world and another person's testimony to an officer can carry a lot of weight if they are an excellent communicator.
Getting involved in others actions that you see as 'wrong' is a dangerous business. I will say that from own opinion I find other attempts at getting someone to adhere to a ruleset whether it's their own or an entities as someone who has issues with control and that, in terms of personal mental health, should be dealt with as a much higher priority.