.badass Domains
medium.com
medium.com
Mike Carson is up to all kinds of interesting stuff in the domain space.
I guess in that case the (claimed) trademark owner would have to sue the (claimed) trademark infringer directly, rather than using the domain registrar as a sort of deep-pocketed extrajudicial enforcement mechanism. I don't necessarily see this as a bad thing. That's what courts are for.
The same is true of straightforward ownership disputes, too.
We don't expect (e.g.) gas stations to be responsible for monitoring for stolen cars and refusing to sell them gas.