To her, it was a matter of keeping her personal life sacred. To the team, it was a message that her personal life was more important than the weekends and evenings they had put in to meet the deadline. Next time, they may not work quite so hard. The emotion and effect on the culture was real, even if it wasn't what the CEO intended. Congratulations from the CEO on a job well done can motivate a team like nothing else.
Silence can demotivate just as quickly.
The CEO hires, fires, and leads the senior management team. They, in turn, hire, fire, and lead the rest of the organization. The CEO must be able to hire and fire non-performers. She must resolve differences between senior team members, and keep them working together in a common direction. She sets direction by communicating the strategy and vision of where the company is going.