Some subway carriages here in Stockholm are, or will be, designated as mobile free zones due to plenty of complaints about having to listen to others conversations over the phone. Personally I find this ridiculous. Sure, I´d like to have a perfectly quiet ride on the bus, subway, airplane or whatever, but when I´m in a situation among other people I don´t go nuts if they talk to each other, if babies scream or couples discuss their dinner plans. Why does everbody get so pi$$ed about conversations that are taking place over a phone? Then at least you miss one half of the conversation.
How often do those that are miffed about some teen/salesperson talking on the phone actually ask them to please talk a bit less loudly?
The one thing I personally have against use of mobiles on an aircraft is if the safety announcements are (more) ignored or disturbed due someone talking, on the phone or to a co-traveller, period.
Oh, I´m seeing some and more ANR hearing protection for travellers, so there are solutions for those that like to listen to nothing.