According to the research for ICANN itself by an university this report estimates that around 28 million domainnames on 100 million don't have WHOIS data that makes it possible to contact effectively the owner of the domain.
You should wonder why security officials at ICANN yesterday were having closed meetings with registrars at ICANN Brussels and asked publicly - with no immediate success but it will become part of the process - if so many domainnames have to be closed down at the root of the domainservers instead of through the right judicial process against the owner itself.
It is strange that using someone's elses identity of even faking an identity is a crime in most countries but shouldn't be when you are buying a piece of land on the internet (which is the internet in fact, a virtual country). When we buy things offline we have to know exactly who is the owner and even if the owner doesn't want to be contacted directly - as is sometimes the case in businesses - than who is the contactable representative who will be accountable if they don't react on questions form the service providers or law enforcement. If you take the money to represent someone you should also do the work and responsability that comes with it.
Than there is the question of cost. But let's talk cost and total cost. It would cost according to some comments around half a dollar more to control the WHOIS data automatically for each domainregistration. Well that doesn't seem much for quality and less crime and more trust online. ANd in the end it will make it easier for the registrars to follow up on the questions and affidavits from law enforcement.
Offcourse this will cost more for smaller companies because they don't have the necessary resources but maybe there is a new industry that may pop up here - permanent address data checking - that could deliver this service to these online services but also to a bunch of others. If there are problems with the address - or it is blakclisted for one reason or another - than it maybe a serious indication that something maybe wrong with your sale and that more information is needed.
ANd yes I can't forget to mention that in the .be domain you can lose your registration when your WHOIS data doesn't have a nonresponding emailaddress but it is totally unclear if they check this before or when changes are made or during the lifetime of the domain. Off course testing one million domainnames is not something you can do manually, but with some filters you can check the emailadresses that were non-responsive. If the emailaddress has been deleted or is non-existant than maybe there could be another problem.
You will see this question popping up again and again in the coming months and you will see probably that the professional registrars with try to make a difference by offering WHOIS services that are trusted and correct and may turn out to be the preferred partners of the bigger domainnameportfolio holders who know that trust and reputation have no price on the internet.