John,
During the test playback, LoadComplete does not use the browser's cache.
LoadComplete emulates some cache functionality, but uses its "internal" cache, not the browser's cache.
For example, LoadComplete neither saves web pages to the cache, nor retrieves them from it, as it does not have to display them to a user. However, it saves and uses the cookie values, since the server responses depend on them (read more about cookie handling).
This "internal" cache works only for one test run. After the test is over, the cache data is removed. So, the next run starts with an empty cache.
