Some search engines allow exact matches by using quotes. Don't know whether LR allows that or how it interprets quotes, but that way it might distinguish those cases properly.
e.g. Folder / Contains / "Nicaragua 2012"
Oh yes, it's not as if Adobe would need to re-invent the wheel. FYI I don't think quotes work like that anywhere in LR, though in the filter panel you can use similar stuff like "!" for "not".
But I feel Adobe are right not to have gone further in that direction - too many people would never discover these methods. Instead Adobe need to refine criteria that are already in LR and make them more consistent. That's why I pointed to the Job criterion where you can create a SC such as "Job / Is / Nicaragua 2012". Another example is "Is Empty" which is available as a criterion for Caption but not for Title, where you need to use "Title / Does not contain / a e i o u" to achieve the same result.