Executive involvement is critical throughout the project - neglect and lack of interest on the part of the executive team and management are a sure sign of a troubled project. Here is a checklist for assessing stakeholder involvement - where does your team fall?
- Stakeholders helped draft & finalize the project charter
- Stakeholders participate in sprint planning
- Stakeholders attend standups
- Stakeholders get (and expect) a demo of work at the end of each sprint
- Stakeholders get demos of work during sprints
- Stakeholders sit with/near the team
I'll leave it as an exercise for the reader to weigh these various touch points. If your stakeholders do few (or worse, none) of these, your project is probably in jeopardy. It may add a little stress to your project to have more stakeholder involvement - but projects that stakeholders don't care about tend to get cancelled.