eg. api.php?action=query&list=search&format=json&srsearch=igor%20stravinsky%20ballet&srprop=score%7Csnippet&srlimit=10

The documentation on the score property says "Adds the score (if any) from the search engine". This would be a very useful property for me to get the relevance of each page to the search string, but it never seems to be returned. Why so? Is there any way I can get the query to return it?

Secondly, I'd like the option to search titles only with the addition of the &srwhat=title argument but whenever I try this I get the error result code "srsearch-title-disabled". Is this temporary or permanent? How can I search on titles only?