Well, we do it one better - we black-hole the network.
I just added another ~60 prefixes to the list after another persistent
attack. I've given up trying to trace them myself (although we do report
it) because the big networks, where this originates, are unwilling to help
in a timely fashion.
If people bitch about the connectivity loss, well tough shit. Better
to have a working network that can get to 99.5% of the Internet than a
completely trashed one with full visibility.
Somehow I doubt there is a big demand for access to your network from these
smurf relays. And if there is 1 person who happens to try, I doubt they will
go running to their admins with "I know why we can't connect... Its 'cause
we're a smurf relay". All the responsive clueful networks have protected
themselves already, what we're dealing with now are the people who don't
understand subtle messages like people blocking their connectivity.
I'm going to have to talk to our lawyers about whether or not we could
the amplifier networks. Most of them are truly large organizations (ie:
universities, big corporations, big national providers, etc) and could
pay such a judgement.
I bet if you just got ONE big judgement there would be a lot more
responsiveness out of some of the big guys... =)