Force a pivottable update on workbook open?

Hi all-

Is there a way to force a specific (or all) pivottable(s) in a workbook to refresh when the workbook is opened?

When writing macros I sometimes put a cover sheet and hide (veryhidden) all other sheets so that the user can't use the workbook unless macros are enabled. In a perfect world I'd like to do the same with a pivottable- if it isn't updated, don't allow the user to use the workbook. Worst case, there needs to be an unavoidable warning for the user that the data is not up-to-date.

What is the ideal way to handle this need?

Thanks!!