If it does, then its broken. The presence of a query string shouldn't have any influence on caching, it means nothing other than "This URI could have been generated with a form and user provided data".

http://search.yahoo.com/search?p=perl has a query string, but the significant content of that page is likely to change less frequently then that of http://perlmonks.com/ (which doesn't).

If a tool wants to do sane caching, then it should pay attention to HTTP's collection of cache control headers.