Yeah.
But you know, eventually standards become real standards when enough people adopt them. In my career I've seen building codes become more standard across the country as local authorities have taken to adopting the same one: the IBC. They still have their local variations, but at least they follow the same form.

Seems to me our signaling standards are pretty much that - there's some variation here and there, but it all follows the same form and is pretty intuitive. However, here's one I like that is probably not well understood: patting the top of ones helmet = single file/no running stops/be on your best behaviour!