Sunday afternoon, the main Sky Club at DTW had a sign that Amex cardholders didn't get free guests. Sky Club members (including Diamond medallions) did. The club was crowded, but not full (most seats taken, it was possible to find two together).
A little while later (my flight got delayed), the North club (high numbered gates) was fairly empty.
A little while later (my flight got delayed), the North club (high numbered gates) was fairly empty.