I have just been running an SRC (Short Range Certificate) radio course today. I have been running VHF radio courses for about 25 years now and have noticed a major change in the last few years.
In the past it would be quite difficult to get students to speak out loud when they were doing the practical exercises and many people would be very self conscious despite my best effort to avoid this situation.
In the last few years this inhibition seems to have disappeared almost completely, the only reason I can think of is the common use of mobile phones in public places. I think that many people have become used to holding conversations in public like this and no longer feel self conscious when talking over the radio.
One of the results is that the standard of the students attending SRC courses has improved drastically and it is now rare for me to have a student on a course who struggles with the practical side. It would be nice to think that this is because I am a better teacher than in the past, but I do not really think this is the cause.
Maybe there is some benefit from those annoying conversations you hear when someone is talking out loud on their mobile phone on the train or in a restaurant!