http://www.securityfocus.com/columnists/329

It's quite long so I'll not quote the whole thing.



It is basically suggesting that if the user gives consent through a EULA to install spyware, and the clearer the EULA the stronger the argument, that the user could be guilty of breach of contract by using an anti-spyware program to remove it.

Thus, the key difference between unwanted and unlawful spyware and "legitimate" software is simply user knowledge and consent. Both might actually collect and transmit personal information, muck up system and registry settings, be hard or impossible to alter or delete, and might disable itself or other programs upon removal. But did you know and consent to having it installed?
The problem is worse for anti-spyware programs, which essentially automate the process of breaching consumer contracts. This is assuming that the consumers actually agreed to the terms and conditions under which the spyware was installed -- generally not a valid assumption. Essentially, the spyware distributors would argue that the anti-spyware purveyors are inducing their customers to breach their contractual obligations, and are tortuously interfering with their contractual relationships with those who knowingly downloaded the spyware.
The article isn't as clear cut as the title suggests but it is an interesting point of view and a hint the way thing could go if the spyware companies continue to try to 'ligitimise' themselves.