Seems to me you can do this with a trigger OnRecordRevert (in FileMaker 12).
Yes you are right David.
However this would require you to ensure that you place the Layout trigger on every layout that requires the logic of the script.
This mixes logic if you are working to a structured implementation like MVC and goes against the DRY principle. The requested implementation of the Get(RecordModificationCount) would allow this to work universally across any layouts with any of the validation settings of the field. The logic would be contained in a single script like a Contoller in the MVC.