We’d Like To Hear You Never, by Lauren Frey has me riled at the memory of the visitors in Watford General hospital use of mobile phones, and it was mostly visitors.
There were signs everywhere saying please don't use them as they may affect equipment, but that didn't stop rude, ignorant, self important people. I'm not sure about the effect on equipment, but the effect on those on the ward and the other visitors was very obvious, and demonstrated why they should be banned, if only for a matter of respect and politeness.
Using a mobile phone was, on occasion, unavoidable - discrete texts were sent by my wife and people on the ward asking for things from home, calls to parents etc. but it was possible to show respect for the other people also on the ward.
/rant