I think I'd prefer a "since you've been a valued customer for X months, we're giving you a discount rate" marketing pitch then a "now that you're leaving us..." gimick.
I can't help but think that the first one gives me a better chance of making more money through more, albeit smaller, rebills by strengthening the relationship.
Of course, if I could somehow make MORE money on individual rebills the longer a member stays that'd be great.
