spree/spree — pull request #2749 by chrishunt (2013-03-25 15:24:58+00:00)
Title: User Promotion should only apply to Users added to the promotion

We noticed that when we removed the last user from a User promotion that the promotion was then applied to every user in the system. This was surprising.

I think it's more intuitive for a User-based promotion to apply to nobody when empty. We have other methods for creating site-wide promotions, so it's not a feature that needs to be here.