How would a PD know you're interested without hourly emails? Forgetting that would be like not FedExing face shots of yourself every day or not sleeping in the PD's back seat so you can discuss your app with him to and from work, home and everywhere he goes. It would be like not assuming the PD's identity and crashing the ranking sessions to make yourself #1. I mean you might as well just give up.
(See I can joke around like this knowing that BKN et. al. will just paste this into some thread entitled "Should I email the group I want to work for?)