Considerations for changing Primary Location via SQL

We have a large number of items that are included on open purchase orders.  Since we import from overseas, our POs typically stay open for months.

We are making some big changes to our warehouse, so next week we will need to change the Primary designation on a large number of items.  Management is determined to do this using SQL, since it cannot be done in the software (because of the open POs).  I would like to know how foolish this is.  Is it just a matter of making the change to PBIN in the F41021?  Are there other considerations?