I received an email today from Wayne Barnes, Associate Professor at Texas Weslayan University School of Law with a link to his article on spyware entitled "Rethinking Spyware Questioning the Propriety of Contractual Consent to Online Surveillance". It can be downloaded here. It's a fascinating read and cites cases where the courts refused to enforce some contracts. Barnes ultimately gets to the heart of the issue with "contract-based consent to spyware". The document is long and detailed but well worth the read, IMO.
Also blogged at SunbeltBLOG.