Back in beta days, the official explanation given was that the DNS updating was a "value add" and that it would never be disabled as a default as a courtesy to corporate customers. Furthermore, MSFT folks have repeatedly said that the workaround is to simply configure your nameserver to silently ignore the error logs.
Well, I'm not going to disable that logging since it has been useful in signalling real attacks in the past. But the thing Microsoft needed to do with this was ensure that whoever is pirating my domain names on their home PCs get error message popups telling them to go to MSN and buy a real domain name. That is, they could be making money here rather than just giving my syslogd a headache. If MSFT would behave more greedily then their customer PCs would be contacting them rather than me, right? -- Paul Vixie