You're right that some people want to know the time in London, Ontario. But most people who ask the time in London don't. In the absence of context, the right

You're right that some people want to know the time in London, Ontario. But most people who ask the time in London don't. In the absence of context, the right thing is to give the time in the UK. If more context is given: "What time is it in London, Ontario," then obviously it should give the time in Ontario, and perhaps remember that this person is an exception to the rule.