An Author's question?

Question to book lovers everywhere: When you buy a book do you automatically check to see where the author is from, and where the publishers are situated?

The reason I ask this question is because the spelling of certain words are different in other parts of the world. I never really noticed this before until I got published by a US company. I try to make sure my books are written in Canadian English, but sometimes in the transfer of my manuscript to my US publishers it gets changed to the US spelling. This is so frustrating for me since almost all of my fans are in Canada so they think it is spelling mistakes! What can I do about this, ugh, nothing as far as I know!!! So I am trying to remember when selling books here in Canada to remember to mention my publishers are in the US and hopefully they clue in to the fact that some words are not spelled the same. A good example is actually right here in my text, spelled is Canadian, but spelt is the US spelling grrr. Which one would you use?