One way you could go about doing this is in your startup Script put something like this:
If[Get ( CurrentTime ) ≤ "8:00:00 AM"]
run your startup strip....
If you want to specify an actual date too use the Get (currenttimestamp)
(Don't lock yourself out.. Create a way for you to get in in case you need too..)
Else if(Get(Username) = "Admin"
Instead of checking the date--though setting the clock back isn't really practical a lot of the time and can cause a lot of issues with your device, you can set your script to update a counter in a field to count the number of times the file is opened and refuse to open after opening it a specific number of times.