I saw a question on Main which looked like a duplicate, so I tried to search for the previous question I remembered. To do this, I entered
oven temperature sugar into the search box at the top-right of the page. The search automatically taggified all of my terms and took me to https://cooking.stackexchange.com/questions/tagged/oven+sugar+temperature , which has no results.
This seems to me to be a clear violation of the UX principle of least surprise. Not only is it rewriting my search in a way which makes it useless, but it takes me to a page which isn't a normal search results page and hence doesn't have the advanced search tips that make it possible to actually get results by searching for
"oven" "temperature" "sugar".
I found the page I was looking for via Google before coming back and attempting various things in the search box. The fact that I felt it necessary to use an external search is a failing of this site.
I don't expect a request for a major overhaul (like making the search box always search and simply weighting tags much higher than occurrences in text) to get much traction, hence this reduced proposal:
When a search which doesn't use the advanced search
[tag]markup would be autoconverted to a tag search which has no results, can it instead be left unconverted?