StepAwayFromGoogle
Where do all of you eat?! Places where no-one says a word, there's no background noise, no background music and the tables are on top of each other?
No, if you read the posts of most posters, it is clearly places where they have experienced families who let their children play with ipads and phones emitting annoyingly high volume of noise. 
In most restaurants it is perfectly easy to play an iPad or similar low enough that you can't hear it at the next table.
If it's perfectly easy to do that, why do you think so many people, like myself, have their time ruined by the sounds of ipads and mobile phones, as per this thread? 
Plenty of people sit on their laptops and all you can hear is the tap-tap-tap of the keys.
That is a very different and much lower level of noise and acoustic effect to the noise from videos and games.
Or have a really loud conversation that you can't filter out.
Which is in tune with other acoustics and therefore background noise. Ipads and phones are not.
I don't think that's the issue here though.
You don't think that the issue here being discussed is the issue? 
Sounds like whether you can hear it or not, there are a lot of posters who just want to judge other parents.
No, nothing here "sounds like" this. You have made that up - you want to believe this peculiar motive, even though there is no evidence of that. I can tell you that when, last weekend, my time with my partner sitting in the lounge area of a hotel was ruined by a family group, where the three adults were on their phones all watching different videos out loud, and the three children were on ipads and phones playing games, the incessant beeping, computerised music, actual music, audience canned laughter, loud tinny voices and adverts travelled to our table two rows away, I can categorically tell you that our discomfort and anger at their rudeness was not born out of some irrational wish to "just judge other parents" but out of our experience being ruined by this selfish, rude and antisocial family. See? Cause and effect? Not cause-secret motivations-effect.
If I chose to give my child an iPad to look at while we're eating (AND it is low enough not to be heard by anyone else) then that's my decision. It's absolutely nothing to do with anyone else. Nothing.
How do you know for fact that it's not audible to anyone else?