Rare occasions when it's necessary
I've come across one (and only one) reason why a company might need to contact a former employee after they've been let go. I worked with a chap who was a named inventor on a patent, dating from his time at a previous company. He got a letter relating to the patent, which he had to sign with his current name and address, and return. Apparently this is normal (he'd been told that it would happen when he dealt with the original patent application, and had agreed to it). It probably helped that he had left the company on good terms.
I devoutly hope that the clause was intended to deal with some equivalent situation. It certainly doesn't seem to have been written that way!
Biting the hand that feeds IT
