Okay, Canadians, can you answer this?

I understand that people from different places have different customs and habits. Tipping, for one. Some places do, some don't. But what about the Canadian double-standard?

When my sister and I worked in Las Vegas, we got a lot of Canadians and most of them didn't tip, just very, very few. But when my sister vacationed in BC (Victoria), everyone expected tips, and got really rude when Julie said, "Since you don't tip in my country, I won't tip in yours".

This has been a puzzlement for some time. Explanations welcome.

Sue