Something tells me that this is an easy thing to ask for, but not trival to implement. It would be great if there was a way to have data type validation in the sample population editor - so that a 10 digit entry for an Object ref of SSN (9 digit fixed length integer datatype), would be caught on entry.
Better yet, if validation would allow 123-45-6789 for the same datatype (just an example - not what I'd do). A similar way to have 1112223333, (111) 222-3333, both valid US phone numbers, but not (1111) 222-3333.
I'm not at all sure how much is appropriate to the tool, or is practical, but some way of getting more real world sample data into the model, more accurately and easily, would be very useful.