That to me seems like something that should be covered by the company's insurance.

Any services company that comes out, ens up with breaking their tools because they used inadequate tooling, and causing more damage? I don't know how they managed to foist that on to your parents.

The issue wasn't the tree roots, it was the rooter company's poor investigation. Video scoping a sewer line is trivial these days.

Oh, they video scoped the sewer, and my parents (father is a lawyer) went after them. Ultimately, the rooter company decided they'd rather go for the full legal battle and my parents decided "eh, we know how awful a legal battle is, we'll back down and not sue."