Sometimes the team count is also helpful if the organizer is planning a dinner or breakfast which I believe is the case at Dover.
Like Sled said, just call or e-mail.
When I filled out the Dover application, I put my name and five unknowns as I was not sure who would be there with me. I just asked them to hold the spots.
Lonestar 24" Vertical offset w/ Insulated Firebox & Performer Platinum
Former owner: Jambo Backyard, Klose BYC, Med. Spicewine, Pitts & Spitts, XL & (2) Med. BGE's, 22" WSM & (2) 18" WSM's, 18" & 22" Weber Kettles