That is not a sound approach:
I think it is.
i) Tor clients will see unexpected connection errors as some destinations are unreachable where they should
Not nice, but better then to lose the complete exit node. Big nodes with their own reassigned IP should of course do otherwise and just move the valuehost abuse spam to /dev/null.
ii) in some legal systems this may mean you can be held responsible for the traffic that is routed via your node.
Example? In Germany you might (or might not) be responsible for traffic you relay. But not relaying part of the traffic doesn't change a thing, legally.