Running a software security company is not normally legally perilous. Suits from disgruntled users are unheard of, and the purveyors of spam, malware and spyware tend not to bother with lawyers. Companies are more likely to sue each other but that’s already in the business plan.

But every now and again, companies from the dark side (allegedly) pop up their heads and have a go, a case in point being the aggressive adware company Zango (formerly 180solutions). This week, the company finally abandoned its rather fruitless legal pursuit of small Aussie security company, PC Tools, which it had been trailing through the courts, no doubt knocking zeros of its bank balance for the duration.

Now it turns out that the company has also abandoned its equally unwise case against the rising giant of the east, Kaspersky Lab. PC Tools is small, but Kaspersky was never going to be an easy one to roll over. These guys are Russians after all, not noted for their legal good nature.

I say “abandoned” because in reality Zango was heading for legal oblivion, having had judgements against them by different courts. In the case of Kaspersky Lab, the judge used the Communications Decency Act as the basis for his judgement.

“No provider or user of an interactive computer service shall be held liable on account of any action voluntarily taken in good faith to restrict access to or availability of material that the provider or user considers to be obscene, lewd, lascivious, filthy, excessively violent, harassing, or otherwise objectionable, whether or not such material is constitutionally protected, or any action taken to enable or make available to information content providers or others the technical means to restrict access to [such] material.”

This is a long-winded way of re-establishing the important right for software vendors to make reasoned judgements about which third-party programs can be considered deserving of being blocked. That is what the people paying their subscriptions for PC security software expect them to do. Regardless of whether Zango has cleaned up its act (as it claims to have, we should add), for the company to have won either of these cases on any point would have had huge implications for security companies.

There is an imperfect but simple definition that security companies follow – consent. If the user consents to a program being on their PC while being made aware of the implications of what they are agreeing to, then it should be considered legitimate. If they don’t, then it is perfectly valid to block it without bombarding the user with confusing “might be” qualifications about a program’s status. If in doubt, shut it out.

The Internet is the one place where paranoia can be a healthy state of mind.