That's exactly the same thing. A branch is nothing more than a commit that you've given a name to. Whether that name is your original branch's name or a new branch's name is irrelevant. The commit would be the same either way.

A junior cannot actually do any real damage or cause any actual issue. Even if they force push "over" previous work (which again, is just pointing their branch to a new commit that doesn't include the previous work),, that work is not lost and it's trivial to point their branch to the good commit they had previously. It's also a good learning opportunity. The only time you actually can lose work is if you throw away uncommitted changes, but force pushing or not is completely irrelevant for that.