Overplanning

My reply is in the context of project schedules. Nobody thinks they have overplanned until they are suffering from having to maintain the plan! :)

It's not always easy to know where the line is between an appropriately detailed plan and a too-detailed plan. Work package owners tend to over-plan by including every single activity that will occur. You don't want a little bump in the road to cause a lot of change to the project schedule.

You can focus on handoff points and milestones in the schedule so those have high visibility - but if a work package involves developing 5 documents, is it really necessary to include a dozen activities for each one? It might be enough to have a "develop document" activity and an approval milestone. That way you still have good visibility into when it will be finished, but you don't have to keep reworking your schedule if multiple revisions are needed.

I think it's fine for work package owners to maintain a more detailed activity list than what's in the project schedule as long they can relate their progress to the project schedule.

If schedule progress updates are regularly causing activities to be added/removed from the schedule, as well as logic changes - and there has been no change in project scope - then that could be an indicator of overplanning in the schedule.