I just flew LGA-CLT as a Korean Air Morning Calm (Sky Team Elite) member on a Delta (Connection) flight. My boyfriend, non-elite (just regular Skypass) and I BOTH got a free checked bag. I didn't know he'd get one, too!

There was no auto upgrade in the system or anything like that even remotely offered. In fact, even though Delta website says Sky Team Elite are Main Cabin 1 - we were put in Main Cabin 3 as it was a V Main Cabin fare (not Basic Economy). As I was confused by that, I asked if they had my Skypass number on the reservation and obviously they did since we got the free bags haha. We still boarded with Main Cabin 1. No one checked or cared even.

Also, after check in, when you would look for any automatic upgrades - the entire seat map was blocked out as full....but oddly, the plane was completely empty. People sat in C+ for free as the flight attendant just said "Spread out if you want."