This works just fine:
The exact same query parameters in an other order appear to do nothing:
Deep in the back of my head I remember somebody talking about details like this being there for compatibility reasons with the predecessor of CirrusSearch. But this specific example just does not make any sense. The parser that parses the users input should extract keywords completely independent from each other, with a regular expression similar to [a-z]+:("[^"]*"|[^ ]*), which means it either extracts prefix:Wiki and intitle:Deutschland as two whitespace separated tags, or the user has to use quotes or \ escapes if this is not what he wanted.