:hijacked: I don't know the answer but I rarely go outside without a cover and it always comes off as I enter a building or vehicle. The only rules I'm aware of for Cowboys seem to come as observations that make good sense (and were likely learned the hard way):
1) Always drink upstream from the herd.
2) Never look directly up at a bird.
3) Don't squat with your spurs on.
Back on track. Are there really rules for when to wear specific types of Cowboy hats or is it more a matter of personal preference? It seems to me like it have more to do with what's practical; hot day and you'll be outside working in the heat then light weight head gear is the best choice and vice-a-versa.
I can explain it to you but I can't understand it for you.
"Any man who thinks he can be happy and prosperous by letting the Government take care of him; better take a closer look at the American Indian." - Henry Ford
Corruptissima re publica plurimae leges; When the Republic is at its most corrupt the laws are most numerous. - Publius Cornelius Tacitus