In newer worlds or servers, each alliance has a cash box limit that is a multiple (depending on the world) of its members' total revenue.
If this limit is, e.g., 24 times the total revenue of the members and all alliance members are producing 1000 monetary units, the maximum cash limit will be, 24000 monetary units. When this limit is reached, taxes will be collected from alliance members but will not fill in the cash box, as it is already full.