Well, if NAF want to set the auction up that way, then he’s entitled to change it thus. Talk to him.
That does introduce an element of risk for him, though, because if he doesn’t get enough for the items he auctions off, someone who does NOT participate in the auction could overtake him. 
The way things stand, the auction doesn’t happen unless everybody agrees to the 50% buy-in, bid or no bid.
Just Some Guy
Holds rules: 16
Has seen rules: 1, 2, 4, 8, 11, 12, 14, 15, 17
And holds these coins: NONE.
Mahaloth
Holds rules: 1, 15, 16
Has seen rules: 4, 7, 8, 9, 10, 14
And holds these coins: 3 Dimes, 4 Nickels, 3 Pennys
Meeko
Holds rules: 4, 8, 9, 10
Has seen rules: 1, 2, 5, 11, 12, 13, 14, 15, 17
And holds these coins: 1 Nickel, 3 Quarters
Has an extra copy of rule 9
MHaye
Holds rules: 1, 11, 12, 15
Has seen rules: 2, 3, 4, 5, 6, 8, 9, 10, 13, 14, 17
And holds these coins: 2 Dimes, 2 Nickels, 1 Penny
NAF1138
Holds rules: 2, 3, 4, 5, 6, 8, 13, 14
Has seen rules: 1, 9, 10, 11, 12, 15, 17
And holds these coins: 5 Dimes, 3 Fifty Cents, 4 Nickels, 2 Pennys, 1 Quarter, 1 Silver Dollar, 1 Toonie
Oredigger77
Holds rules: 5, 13, 17
Has seen rules: 1, 2, 4, 6, 8, 9, 10, 11, 12, 14, 15
And holds these coins: 1 Dime, 3 Pennys, 4 Quarters
phi2dao
Holds rules: 1, 2, 3, 14, 17
Has seen rules: 4, 5, 8, 9, 11
And holds these coins: 1 Dime, 1 Penny, 2 Quarters, 1 Silver Dollar
sinjin
Holds rules: 6, 7, 10, 11, 12, 14
Has seen rules: 1, 2, 5, 8, 9
And holds these coins: 1 Nickel, 5 Pennys, 1 Quarter
Has an extra copy of rule 7