I guess "often" is relative, but this happens to me pretty regularly.

I live in Canada, and it's not always obvious if an American company ships here or not. If the answer isn't trivial to find, I'll do this:

  1. Add something to the cart
  2. Start the checkout process as a guest
  3. Fill in the boxes that pop up during the checkout process
  4. Close the tab when I see that the country dropdown only has USA available

Stores built with Shopify do this so consistently that I have to assume it's an out-of-the-box feature you need to opt out of.