[Aachen]

Ah right, I was figuring most of those misconfigured udp services (dns, ntp, ...) were running on servers rather than regular home IPs. That does make it a little different.

Still, if an ISP has had multiple abuse reports for the same subscriber and they're not doing anything, after some time it starts to become reasonable to block this IP, and in a further escalation, this ISP's ranges altogether until they clean their act up. I remember getting the Internet connection blocked as a teenager on an XS4ALL connection for being an ass on the Internet (I tried to DoS a domain squatter that tried to sell a domain I wanted for a thousand times the price with no added value). The abuse desk which I had to contact to unblock it took my promise to not do it again seriously (as did I), not sure how other ISPs handle this.