[hunter2_]

Honestly this sort of deferred validation exists as a standard feature of certain modes of data intake that are often criticized for same, for example paper forms (the "required" fields can be left blank), or creating support tickets via email (required fields stay null until an agent updates the ticket via web UI). At some point additional round trips may occur to pay back this debt, but debt is a powerful tool for that person in the field who needs to move onto other things until the dust settles and they can pay it back.

[pmontra]

Paper forms can be filled in by different people with different roles at different times. Customers can fill in their personal data and possibly leave blank something they don't understand. A clerk can review the form, ask the right question and fill in the missing field plus the remaining ones.

"Fill in what you know and leave the rest to us" is a simple and cheap to implement GUI compared to a full fledged workflow. It could bootstrap a process quickly at the cost of some extra labor in the customer facing department. Maybe they have that extra bandwidth and the sw developers don't.