I'm in Australia and what I tested seemed to indicate for most results, there were indeed correct. Only sampled five from the page, could have been some results in error. Note, when I use google, the only links they offer to me are obfuscated so it's a matter of having to click on the link - unknown result which is yet another reason I don't use google any more.

Duckduckgo - total fucking fail. I'd been noticing duck duck has been a bit of a dud on results last few weeks and have resorted to using yandex for my trickier searches.

Yandex. On the money. No erroneous results - operator filter working as expected