>In the mountains of Italy, drivers give a short honk before entering a turn on a serpentine road, which usually can't be seen around. If there is no responding honk, they will take the full width of the road (making the very tight turn easier and faster). Tourist drivers have to pick up on this :)

It seems like it should be illegal (and also partly suicidal) to go into the opposing lane in a situation where you cannot see if there is an approaching car. You're relying on someone in an opposing lane hearing and understanding your horn, for relatively little gain, and potentially fatal results.

Any situation where you can do everything 'perfectly' and you have a significant chance of dying or killing someone because someone else doesn't notice is a good situation to avoid.

If you hit someone's car under these circumstances it would be criminally negligent in my opinion.