I use it all the time. My biggest issue is I frequently get 0 search results with it on specific searches. It may not always have a result, but I don't get returned results that don't include the quoted portion.
> The problem is that you're assuming search is deterministic.
I am not assuming search is deterministic.
But even in a generally non-deterministic system, some things should always stay true.
For example: When doublequotes means "exact match", any item that doesn't contain an exact match should not be shown.
I also understand that a webpage might have changed since it was indexed, but I have a really hard time believing all the false matches I have wasted time on over the years relates to websites suddenly changing between the time when they were indexed and the time when I visited them.
Maybe the exact match is in metadata or in hyperlink anchors pointing to the page. More in general, each search will hit thousands of machines and there will be always approximate behavior. It's not just about what you are searching and how, but also what others are searching. The most deterministic aspect of it all might be the latency budgets on the backends and indices. You could tweak those, but then costs, failures and abandonment rates would go up, too.
Edit: Downvote all you want but this is documented.