I never understand any blanket-type rules.
If we are eating at the table together, I would absolutely 100% expect screens to be turned off and put away, in all cases and for all reasons.
In a restaurant, I would usually NOT take younger DC to the kind of restaurants that are going to take long enough that a bit of colouring would not work for them. Occasionally, when they were very small and I did need to, I might have allowed a screen while they waiting - on silent or with headphones.
Someone routinely checking their phone while out for dinner with me I'd consider rude. BUT... I would absolutely accept if someone said as we sat down, "I'm really sorry, I have to keep my phone handy to keep an eye out as I am a bit worried about whether DS is well enough to have a babysitter so I've told her to ring me if he gets worse" or similar. Then I would expect call screening/texting so that only calls/messages from the babysitter are responded to.
I let the DC watch screens while eating breakfast - it's not a family activity and usually while they're eating I'm making packed lunches, tidying up etc. At their age, we watched cartoons (or the news, if dad was in charge) while we ate breakfast.
as a family, we do not all eat together every night. So on the nights that we are not, for whatever reason, it's entirely likely that one or more of us will eat while watching tv/iPad.
So no, there's no blanket rule but broadly, in a social situation, no, I would expect no screens.
Incidentally, when we were growing up, we had no tv at dinner and, if the landline rang, whoever answered it took a message - no one was allowed to take a call during dinner.