We went looking through the machines that are reserved for that purpose today and found several machines that we thought we were using.... and we weren't actually using. This is actually good for us, because we thought we were out of machines. But boy does it pay to go check that what your lists are telling you! Just like we double check bug fixes, we also need to double check resources we think we're using.
Lists, even updated lists, aren't always accurate. Test those, too!