Old laptops are also notorious[1] for being fire bombs with bad batteries.
If I was a hetzner customer I'd be pissed if my server burned because someone's 2 minute battery life 10 year old school pc was hosted in the neighbouring rack.
Doesn't seem like a great business idea.
[1]: anecdotally, seems everyone has a laptop lying around with a cursed battery
That's what I was thinking too, don't data centers have policies about this stuff? I wonder who'd be liable if your laptop burst into flames