...wut? That's ridiculous. What evidence is there that there are groups of nefarious hackers out there spoofing analytics data on people's websites? I don't think there is a need for this solution because the problem doesn't exist. If I wanted to mess with someone's websites, there are much better ways than injecting some false data into their Google Analytics.
The same people, who, say, use a housemate's phone number for their Safeway card so that Safeway can't determine their shopping habits?
If there was an easy way to do it, many people would want to.
It's clear that there could be an easy way to do it if you put, like, two good hours of work into it.