System allowing creation PO's with vendors that are not assigned to the company code.

Hi,

A user was trying to create a PO under Company Code 2000 and selected a vendor assigned to Company Code 1000.

This should throw up an error , however the system allowed the USER to assign the vendor to the PO. ( I also confirmed that the vendor was not assigned to Company Code 2000 ).

I am hoping to get some inputs from experts here on this one.

Many Thanks,

Sanjeet