Okay, here I have to come in with my academic background in cultural studies and intercultural interactions:
We don't usually think "what would a Canadian do?". But subconsciously that's what everyone is doing all the time in all parts of the world.
If I am a German and in Germany, and there is an older man in a restaurant who is talking very loudly, I don't stop and think "what would a German do?". I would lean over and say "excuse me, could you keep your voice down a bit?".
But assumed I sit in a restaurant in southern Italy or Turkey. Those places are not far away but still I, and I think quite a lot people, would wait a moment and think "what would a local do?". Does this person behave inappropriate in public and by the local customs it is appropriate to speak up when someone feels annoyed? Or supposed I'm in China. Am I as a 20-something allowed to say such a thing to an older man, or would I have to give one of the older people from my group a hint to speak up in my place?

Many people never do it, and they are the ones that in all places of the world are called "Those damn stupid tourists!" in the local language.