Limit the number of times/date a .xls file can be opened?

[JTD1]

Sometimes I send out spreadsheets and 3 months later I see my spreadsheet being sent to someone else. The data is out of date or being misrepresennted. How can I limit access the file to force the user to come back to me for the most upto date file. By limit, I mean the file can only be opened a fixed number of times or the file will expire at a fixed date? I've tried a dialog box that fires during the workbook open event (but its not remotely tamper proof). Just an outline of things to do would help? Thanks.

 

[Zathras]

Instead of a count of number of times opened, why not just compare today's date with a date in the file and limit it to a fixed number of days?