The ballista has an unlimited supply of ammunition, and this is not a bug; it’s just how it’s displayed (as far as I remember, it’s a coding glitch). This happens in all versions of the game and is allowed.

P.S. Mikki, you have been accepted.

P.P.S. The organizers also need to take care of their families, and half of Saturday is usually spent at markets/stores. So, you shouldn’t constantly nag that the organizers are unavailable; just wait a little, and we’ll try to respond promptly.