"Careless talk costs lives," was the wartime reminder to be careful when discussing sensitive information in public, or at least on trains, for fear of enemy spies who might be lurking on the luggage rack.
Business travellers might usefully be reminded of this when sharing their concerns about their own companies while hanging around in airports, particularly on a major petrochemical travelling route.
The Blog was waiting in line at the boarding gate, when she was joined by two fellow travellers, evidently process engineers in petchem companies.
"Where are you going?"
"Louisiana, Baton Rouge, the FCC's down."
"Ah, the big one."
"Yeah, third time this year, you?"
"Texas City for two weeks, we've had a bad start to the year."
"Were you in the office on Friday - see the memo?"
"It's a good package, but you don't want to be on the job market now. I've only got a few years to go."
"You could move out here and go onto local terms. The market's still looking good there."
(And more of the same, halted only by taking our seats on board.)
"Even the walls have ears," and that lady standing next to you tapping on her Blackberry might just be a reporter.
For more on Baton Rouge and Texas City plants, click on ICIS news.