Cultures whose etiquette is rooted in now-inapplicable cultural situations

[Malthus]

@Apollon

Please don’t perpetuate that urban legend! Not only do we know where the military salute really originated, but even if we didn’t, there still would be no plausible reason why to believe that it originated with medieval knights. Consider: the knights disappeared in the late 1400s; saluting wasn’t adopted until the 1700s. What kind of tradition gets into a 200-300 year hiatus and then suddenly becomes universal again?

The very article you linked explains real origin of saluting in the very next paragraph:

Heh, it is still a good example - only, moved down to the early modern era.

Saluting survived even after military headgear ceased to be cumbersome and elaborate.