In negotiations or in a hierarchy, this is a strategy of holding back the commitment of some resources. The plan is that they might be subsequently required by a customer or superior and, when provided, gives them the sense that they have gained a considerable concession. This is named after Gypsy Rose Lee (1911-1970), American ecdysiast (stripteaser), who advised a stripper to pretend that she had completed her disrobing but still had one or more garments that could be removed and had been planned to do so. This caused the customers to clamor for her to remove more, and when she would seemingly reluctantly did so, it would, give them the sense of having gotten something extra.
On my original proposal, I used the Gypsy Rose Lee strategy by not listing some things that were planned because I knew that they would be requested and I wanted to give the impression of them having gained some big concessions.