I highly doubt you will be asked for ID. Perhaps if you somehow get a SLC crew on one of the segments. Funny enough Delta inadvertently served me my first alcoholic drink. I was flying DFW-ATL and the MD-90 has a lot of wind noise at the front of the aircraft. I ordered a Fresca and somehow the flight attendant thought I said whiskey and that's what she brought me. A little stiff going down but fortunately I have a very good poker face.