Today, only shortsighted companies believe that the utility of employees is exhausted on the date of termination. In fact, "alumni" (sounds better than "former employees") who have been properly treated at time of exit can be a perpetual asset for the firm. They can provide a point of connection for business development, serve as a referring group for recruiting and occasionally provide a flexible pool of expertise for projects requiring specialty skills.
Yesterday evening I had the opportunity to attend the first gathering of Boston Accenture alumni at Symphony Hall. This gathering, attended by over 100 people (a 40% response according to event organizers), was a lively event. Life changes were noted (a lot of marriages - consultants do tend to mate once they are off the road) and successes celebrated.
What was clear is that people were happy to see one another, a real payoff for attending. And for Accenture (which looks for a "value proposition" under every rock) the payoff was equally clear. Good relationships are good business.