Well we certainly won't put any advertisement on our customers domains. I don't know what kind of customers you have, but ours would be up in arms and I think rightly so. We would like to have no nameserver entries at all for those customers that don't additionaly buy our hosting solutions.
It's become a standard practice - at most registrars (and resellers) if you don't set up a web site and have their nameservers listed, the registrar/reseller will point your web traffic to a parking page.
I probably should rephrase my question: For what technical reason is it mandatory to have two default entries? I know that there are rules passed down to Tucows but what's the reasoning behind them?
You mean you want the rfc? Google is your friend.
I'm guessing it's more of a Jon Postel-ish thing, perhaps left over from the days when domains were free - if you are getting a domain, it's assumed that you want to use it, and since you can't use it without nameservers you should be required to specify a couple when you register the domain. Some people still consider the option to have no nameservers assigned to be a bug.
-Russ
