I haven't had much of a chance to nonrev on DL, but I vaguely remember being able to choose S2 or S3 on checkin when I went to YVR. Since SkyWest is a sister company of ASA, I'm guessing that our benefits are similar. Oh, and I'm not even Delta-dedicated (I don't handle DL flights, so I only get ID95s on flights that aren't operated by SkyWest and my parents get ID90s)