Interesting and technical in-depth review of Netsol squatting whois searches- and warning about using the Linux whois command. According to this article, running a whois command on a Linux box or searching for a domain at Network Solutions results in Network solutions squatting on that domain for 5 days- during which time it can only be purchased from them- Network Solutions apparently admitted the practice, and tries to justify it as good customer service. See article below.
http://commandline.org.uk/more/squat-for-the-win-2008-01-09-03-36