Stage 1: Shotgun 15 (or however many) dealers with an initial email.
Stage 2: Send a followup email to the handful of dealers that actually respond with legitimate interest in making a deal.
What Randy was saying is you can “pretend” you already did stage 1 and email the dealers you may actually get the car from, making them think they have “made the cut” of a larger bidding process. Then they may be more responsive in negotiating a deal.