That would certainly suck. The worst in my experience (at least recently) are standups where the PO shows up, then proceeds to get in long-winded discussions a

That would certainly suck. The worst in my experience (at least recently) are standups where the PO shows up, then proceeds to get in long-winded discussions about features and implementation, and invariably tries to guide priorities for the day. 90 minutes later... For a time I was managing a team that used this PO, and I quickly banned him outright from standups. Told him to keep his guidance granularity at the sprint level, make sure his stories were written well enough to not require constant elaboration, and otherwise leave the developers alone. He could show up for sprint review & planning. Standups were just to unblock anyone who needed it, and should only last a couple minutes.