Hopefully devs will fix this and it the mean time admins make it a banable offence to spam weapon racks. I can't think of any scenario where you need more than 3 weapon racks..
Castles
Attackers - 1 at spawn, 1 at catapults and 1 at forward spawn
Defenders - 1 at one side and 1 at the other (or 1 on wall, 1 ground level)
villages/battle
Attackers or defenders - 1 at spawn, 1 at forward spawn