With the "Basic" fivestar theme, users must click the "Cancel Vote" button twice to effectively update the widget's display.
One click on the "X" only changes the description text "Your Rating" to "None." Average Vote and Total Votes continue to display old information (until the page is manually reloaded).
Two clicks on the "X" will finally blank all the stars, and clear the Average Vote, Total Votes, and Your Rating text (without a manual page reload).
Can send a link/login if necessary.