I can assure you they do this stuff. They are not as blatant as Verizon. We have ported some of our own circuits and with in a few days someone here got a phone call about a renewal or new offer etc from the rep on that circuit. They never mention that they know the numbers are being ported but it's quite odd that you don't hear from anyone on a 3 year old circuit until the there is a port request.
Just because you never got a renewal offer before doesnt mean someone else hasnt. It's the way businesses work. And you can assure me all you want the fact is VZ got CAUGHT and their is not any actual proof that anyone else is doing this.