He uses as an example a warning sign that used to be on all trains in Italy.
The sign had:
In a nutshell, along his analysis, the Germans being a very disciplined people, they need a direct order: DO NOT lean out of the window!
E' pericoloso sporgersi dal finestrino
Please do not lean out of the window
Prière de ne pas se pencher au dehors
The English (UK) have the fame of being very polite, so they are asked to: Please, do not lean out of the window.
The French are said to have something that cannot be translated, which is nonchalance so they are told: You are asked not to lean out of the window (which leaves them a sort of free will, they are asked not to do something, but after all it's up to them).
The Italian is a plain statement (actually an obvious one): It is dangerous to lean out of the window.
You cannot tell an Italian to NOT do something (as the effect will be that he/she will attempt it first thing), nor you can tell him/her to do something Please (as the reaction would be: Please who? What do I get if i comply?) so everything is left to common sense (you have been told, but do whatever you see fit).
How would this translate in other places/countries?
I have two propositions for the US :
It is an offence under Federal law to lean out of the window.
The Surgeon General has determined that leaning out of the windows is dangerous for your health.
What about other countries/languages?