LOL
Now that my kids have phones to take to school (their passes for public transport are on there and sometimes teachers will open up the WiFi and let them do stuff and the secretaries are apparently hesitant to let kids use the landline to call parents when they need to), the most serious conversation I've had with them is to please not look at other people's screens... I remember Rotten dot com and I know that some kids like to shock others... so I've told them there are things you can't unsee and things that will cause nightmares for weeks.
We also have a rule that us parents know the passwords and will occasionally go through their messages. The phones are not to be taken to bed. The parental controls are set so there's a time-limit on the screen being on and on the apps that can be used.