Is there a way to configure subscription clubs to not allow customers to add out-of-stock items to their upcoming shipment?

Any products added to the pool of products in Step 2 of the subscription club are available for club members to add within the minimums and maximums you have set. We HIGHLY recommend only adding products that have enough inventory to fulfill all club orders. 

We recommend using Step 4 in the subscription package to properly forecast required inventory for the club shipments that are currently built and remove any products that have low available for sale inventory, to ensure they are not included when the system builds the upcoming shipments.