I worked with a Product Owner who made specific delivery commitments to their business partners and peers without consulting the rest of the team. They set unrealistic expectations and wanted to push the team to meet the goals, even though they were not advisable. It is my job as a Scrum Master to shield the team from this kind of chaos, so I asked the team to keep working at their normal pace while I worked to facilitate a solution to benefit everyone.
I met with the Product Owner to remind them that delivery commitments are a team effort and that it is expected for the development team's feedback to be included in the process. They apologized for going around the accepted process, and we collaborated on a plan to move forward.
I asked the team to consider taking on a few of the promised stories at the end of the current sprint if they had any free time. I let them know this was not a requirement, but anything we could do would add value for the customer. It turned out that we were able to work on a few of the smaller requests even though they were not part of the original plan.
I met with the Product Owner and their peers to deliver the news that we could not complete the entire scope as promised. They were disappointed, but the discussion served as an opportunity for them to learn more about the Scrum process, which helped us to avoid similar future conflicts. They also greatly appreciated the extra stories we were able to include on their behalf.