Where are you getting this is the purpose? It certainly wasn't spelled out in the email. Sending an email on a weekend when they wouldn't be expected to check their email is an odd way to go about it.
> If they are part of the executive branch and the president or one of his delegates ask for it, they are in the chain of command.
Which one of his delegates is asking for this? It's again not been communicated in any way under whose authority this is being done. Elon tweets are not official communication and depending on the hour of the day he's either in charge or has no authority.
> My guess is that guy probably won’t have a “government email address” and if he does, he responds with “I worked xx shifts for xx hours running the scanner at the airport per my prescribed job duties requires.
Your guess is wrong. All employees of the federal government get an email address. And many contractors. Your reply doesn't sound like 5 bullet points as required by the email.