They'll respond and say the official policy is length of stay.
Enforcement is totally different. Since there aren't RFID chips, they have no way of knowing when a current design cup was purchased. As PPs said, let's just enjoy the unofficial benefit while we have it. I dont have a mug/cup, but for anyone using an older one I say good for you and go for it. I'm not going to report it to a CM.
In fact, I would think that anyone using an older cup knows more than me anyway, since this is my very first time at AUL (frequent visitor elsewhere in HI).
Besides, it's Hawaii. Laid back island life and Ohana is everything here.