Google announced that it will begin to “preemptively disapprove free standard listings for products that are marked as out of stock in the product data in Merchant Center, but are in stock on their landing pages.” I do not think this applied to paid listings, just the free listings.
So if you submit a data feed and there are products in that feed that are labeled as out of stock, but the landing page on your web site shows them as in stock – Google will disapprove them.
Google said “to avoid having your products be preemptively disapproved, make sure that your Merchant Center product data’s availability values accurately reflect each product’s availability on its corresponding landing page. It is recommended that you enable automatic item updates in your Merchant Center account to help reduce the likelihood of inconsistencies.”
If you would d like to exclude products from your listings, use the excluded_destination attribute.
Forum discussion at Twitter.