Emergency PO Number of Auto Create Form

Hello All,
I was just curious to know what is the real purpose of "Emergency PO Number" On Auto Create Form in PO module. I am just trying to create a PO using Auto Create feature in EBS and am just wondering as to why emergency PO number is a field in this form even before i have created any purchase order. I

You may review the screen shot below.

Please share your thoughts or comments. Thank You in advance.

Regards,
Kazey Boy