Isn't the point of the web of trust that you can do something about the cousins/dudes out there? Once you discover that they sold out, even once, you sever them

Isn't the point of the web of trust that you can do something about the cousins/dudes out there? Once you discover that they sold out, even once, you sever them from the web. It doesn't matter if they took 20 years to succumb to the temptation, you can cut them off tomorrow. And that cuts off everyone they vouched for, recursively, unless there's a still-trusted vouch chain to someone. At least, that's the way I've always imagined it working. Maybe I need to read up.