Andrew Yarnwood wrote:
I have a proposal for dealing with (punishing) people who make loud
business phone calls on trains (or any other public transport). ("I'm
on the train ... buy! ... sell!")

Record the calls or make some note, especially if there's anything
that sounds confidential, and publish transcripts or summaries on the
web or a newsgroup.

Comments?
Suggestions?

I travel in the quiet zone and if someone is on the phone and they give
out their number I call them back later in the day to remind them of
their error and point out that they were careless in giving out such
information in the quiet zone.

I don't wait to listen to their excuses, four letter words or threats -
but then hang-up. CLI never withheld from my disposable PAYG handset!