The WHOIS registry is the domain name systems' legacy database; it contains names and contact information of all those who register Internet domains. The contents of the database have been publicly accessible to anyone who wanted it.
Companies, intellectual property holders, and law enforcement authorities favor open access to the WHOIS database on the grounds that it helps them go after phishers, trademark infringers, copyright violators and others. Privacy advocates oppose unrestricted WHOIS access on the grounds that it could expose individual domain registrants to spam and unwanted surveillance.
One of the better proposals was one to shield the contact information of individual domain registrants while making that of commercial registrants publicly accessible. Also, access to shielded WHOIS information could be provided on a one-time basis or on an as-needed basis to those who could demonstrate a valid reason for access to the information. A warrant should reveal all if need be.
There are those who would avail themselves of a proxy, for good or for ill, and law enforcement will always need to be vigilant and perform their appointed tasks to discern the difference.