For a non Xtra user, that has Xtra DNS servers hard coded, 90% of DNS requests will probably work because Xtra's servers have much of the nz internet namespace in their cache, (or the servers are authorititive)
The IP address 202.27.184.3 is a virus, it seems have spread into the configurations of many NZ computers, I think it is one of those "it just works" scenarios and computer technicians have used it as a default fix for many "wierd" DNS issues.
Once Xtra disable recursion for non Xtra customers, those same techncians will be challenged with trying to diagnose a very intermittent "page can not be displayed" fault.
One does have to ask tho - "Is this Xtra's Problem?" Would the better solution not simply be to do what Ted has done here - get the information out ahead of time - so that when confronted with the problem, those very same technicians know to look at the local DNS config first? Would it not be best practice for technicians to use the local DNS server or local ISP's DNS server over using Xtra's for non Xtra customers anyway, and does this move therefore not simply encourage the lazy or those with non-best-practise habits to plan to change this? Certainly for those who I provide support to privately, I know to look at DNS server specified-fixed as a potential issue going forward. Not that those people are set up to use Xtra where they shouldn't, of course. I say get the info out to those who need it - IT Contractors etc - as soon as possible. One would assume that with NZNOG having been in the loop, ISP tech support can be prepared for the possibility. Using Xtra's DNS for recursive third party lookups is one thing, but relying on them when you have no business relationship with them? Thats hardly Xtra's fault. Mark.