Maybe you can just issue a warning?

Data|validation|Alert Tab.

You have Stop|Warning|Information options that you can choose from.


Jim Johnson wrote:

Is there a way to create a validation rule that is used 90% of the time and
also to specify an exception for the other 10%? If I had a field that was
intended to display a date and set up my validation for the date, could I
then create an exception that would allow me to type "tbd" for those dates
that have yet to be determined?

--

Dave Peterson