I would love to attend an event without cell phones, and I don't see anything rude about requesting this, as long as another method is provided for emergency contact if someone does need to be reachable 24/7. I'd really like to see this idea catch on.
I find it very distracting to be surrounded by the constant flashes from photos, typing sounds, ringtones, and vibration noise every time a text comes in even if the ringtone is turned off. I also find it rude for someone to pull out their phone in the middle of a conversation with me.
I do understand the introvert argument -- I'm one too. I solve it by going for a quick walk outside or chilling out in the bathroom for a bit. I think pulling out a cell phone and surfing the internet at a wedding reception, so that you can avoid talking to people at your table, is extremely rude.
I'm trying to think of any other item in history that wedding host might have"Banned" rather then just speak to the potential offend guest personally. I'm thinking mom talk to Aunt Mary I don't want them sneaking beers/their skateboards/turning a table into a card tournament like they did at other event. Jumping off from that example telling all the guests " all paying cards are banned " I think would be bizarre and some people might take offense at being told to not do something they would never think of doing. I cant think of anything else that has the same potential for rudeness that has become such an important part of our lives.
The leave this as an emergency number, I'm not sure people actually know how to do that anymore. Using a made up emergency. The baby fell out of the crib. Cell phone babysitter calls parents and they proceed to call ambulance/go home/ determine the baby is ok go on with evening.
Call venue. "I need to speak with Mrs Smith." (if the venue is not prepped that they will be receive emergency calls and/or has not prepped every person answering the phone) There is no Mrs Smith here (of course no one named Mrs Smith works there) "The baby fell they told me they would be there." , "I'm sorry but you have the wrong number." on and on .... There are people under 20 who have never called a person other then directly on their cell or home phone. Who've not seen anyone call a business even in a movie and say "Hello there has been an emergency I need to speak to Mrs Smith , she is a guest at the Jones wedding/she's having dinner with some friends. I must speak with her urgently " This kind of calling etiquette isn't taught anymore there hasn't been a need in 15 years. I think the confused babysitter and receptionist would be likely to figure it out after a bit of confusion. More troubling to me, there are 20 people who if they were in a car accident that evening I would leave your wedding to go to the hospital. 20 years ago these people may not have been able to get a hold of me , now they can and I want them to.
Flashes going off , I think once cameras became affordable and compact people took them to weddings. I recall a trend where the hosts would provide a disposable cameras at each table. I think there are more of them. Film was expensive so picture were limited by cost a bit and I didn't used to take my digital camera or before that film? camera(is analog the right word?) with me unless everywhere even to weddings it was too much to carry and remember. Now there may be 80 -100 with virtually picture and video taking capacity. So I understand your point and the pp who talked about looking into a sea of phones( the guests using the zoom to see better , so they were really actively engaged in the event not tuning out.) creating a barrier. 5 guests using a roll of film with flash wasn't rude though. I'm not sure 80 guests taking 10 or even 20 pics each is rude either but annoying sure.