There is no deception. They are working to build momentum for Cruz, and part of that will be to announce high-profile conservative endorsements over an extended period of time. You announce one endorsement and give that time to have an effect, then the next endorsement builds on that effect, and so on. If you announce all of the endorsements at one time, you get a one-time bump and that is it. This is smart politics on their part, but there is nothing deceptive about it.
But yes I agree, probably good politics. But not necessarily total upfront honestly.