Here's an idea...
What we did within our implementation is to eliminate the need for the user to have to select which sheet to export altogether. The users found it too confusing. Rather, we provide them a download button, when they hit the arrow, they can choose the view and then the download button appears to go to crosstab. As part of generating this list, we tell our authors that if you don't want it showing up in the download list, then prefix the worksheet name with [X] and then we have logic to eliminate it from the list.