I've given people basically the above points and managed to persuade them. But like I said, only if they ask. Some people don't wanna hear it cuz they think law school is their only possible life plan, so if you tell them it's a bad plan they get mad.

Also you can find out what schools they are targeting and link them to http://lawschooltransparency.com. Amazing to see the jobless rates of students at even pretty good schools.

Have you asked them to explain as clearly as they can why they want to go? Easiest way to change someone's motivations is to speak to those motivations.