Watermarking has been around for some time. IDA has used it for many years. It's only real effect is to punish the original, legitimate owner, who either gave away his copy of the software or, more likely, left his computer unattended and unintentionally allowed someone to download it.

If the IDA model is any indication, watermarking as a protection scheme is a failure. They are very selective of the people they will sell to, usually government agencies or companies they know something about. They do not generally sell to individuals. Yet whenever a new version is released, it quickly makes it's way into the 'public domain' within a few weeks. The ftp of this forum is a good example.

In practice, I doubt that DataRescue can do very much to punish the offender. They can hardly threaten to stop selling to large customers. That would really cut into profits. All they can really do is hope that the threat of punishment will deter people.