"Policy Change" emails are terrible ways to address this sort of problem. People hate these sort of policy changes not because of the email, but because of the policy. It is trying to solve a productivity problem by imposing on everyone a new burdensome, non-productive task.

If you think employees are not performing to expectations, their managers should tell them that clearly and honestly in person. If necessary, those particular employees should be limited from working at home, or tasked with additional reporting. That way the "punishment" fits the crime.

As an aside, the second email is long and full of forced friendliness and awful corporate speak. I mean, every paragraph has the work "collaboration" in it, except the last one--which calls the managers knuckleheads. I think emails from the CEO should be short, honest, and clear.

Subject: Falling Productivity

Team, We are seeing falling productivity, and the pattern seems to be related to working from home. It should go without saying that we must maintain high productivity if we want to grow and succeed as a company. We need to get this fixed.

In the next few days your manager will schedule a meeting with you to discuss in detail the problem and how we might solve it.

Thanks, - CEO Guy