I think the bigger point is that companies like Equifax shouldn't be using ID numbers at all in the way that they rely on them. They use SSNs as a database ID crutch to keep from having to do the actual leg work of talking to people, verifying/reverifying the accuracy their data, and basically doing the job people pay them to do.

Others on this thread have suggested that storing information that can cause me to incur a liability should require insurance against such a damage. I'm confident that with the right incentives in place, commerce will proceed without getting bogged down.