Maybe in the United States, but what about elsewhere like China, India, Europe, etc....In the United States, all the employer has to do is provide a convincing argument to the judge as to why this type of discovery is appropriate. The judge then has the option to accept or deny it.
If I was going to keep myself completely anonymous, then I would not use a credit card for the subscription service in the United States or anywhere else. I noticed the Anonymizer allows you to send in a money order to them so you do not have to use a credit card. I would also go to one of the many coffee shops and fast food locations that has wi-fi versus my own residence so they have another road block.
There is also another way of tracking through the installation of regular and flash cookies. I would clear the cookies before browsing anonymously. There is a program called CC Cleaner that will clean out the computer.
