Depending on the supplier process, this may allow someone to set up a fictitious supplier and enter a Req against it. Then if this is done by someone in purchasing, the Req could be converted to a PO and an invoice submitted. The risk depends on if a person can approve their own req and/or PO (determined by the Document Types). Without a supplier approval process for all new suppliers suggested by buyers there can be significant risk here. Requisitions allow for the suggestion of a supplier.