The Product Owner's authority to change and update the Product Backlog is typically unlimited. Is there ever any exception?

The Product Owner's authority to change and update the Product Backlog

1.	The Product Owner's authority to change and update the Product Backlog is typically unlimited. Is there ever any exception?
Answer» No. The ENTIRE organization MUST always respect a PRODUCT Owner's decisions. For the Product Owner to succeed, the entire organization must respect his or her decisions. No ONE is allowed to tell the Development Team to work from a different set of REQUIREMENTS, and the Development Team isn't allowed to act on what anyone else says. The PO can remove the product backlog items if he/she feels that is not a high priority one. Anyone can add an item to the product backlog. But, it is the PO who decides what happens to the PBI.