I suspect they are encouraging people to lie on their applications, which gives companies a defense to any sort of fired for cause lawsuit.
How many applicants will be inspired to lie because of my absurd requirement on the job spec? Of those applicants, how many will I hire? Do I only hire applicants who have lied in order to be protected so I can later fire them? I wouldn't hire someone who lied on their application in the first place!
I've never had a legal department recommend something so silly as this, and I challenge you to find one that does. If you want certain protections for the company in an employment agreement, you put them in a contract.
There are three of the standard answers that come up any time this topic does.