Without a doubt, that would be the first car I ever owned, a Renault 21 2.0 diesel that was about 12 years old when I bought it in 1999 of thereabouts, for slightly north of € 1000.
It had some rust, but the worst part about it was that it was slow as molasses. It would do 0-100kph in 25 seconds on a good day, with a top speed of 125 on the speedometer. I laughingly called that my highway cruise control 😁
At the same time, I have very fond memories of that car, as it allowed me to visit my then girlfriend (and current wife), and had loads of cargo space. It also handled speed bumps incredibly well, so I didn’t really need to slow down for them. It also helped that I never had any reliability issues with that thing, until it was totaled.
Indeed, just let them be responsible for waking up on time. If they wake up late, the consequences are for them. Don’t want the offered solution, find your own, it’s not my problem if you’re late for school/whatever.