I'm traveling between Chicago MDW and Orange County, CA SNA and am trying to use the lack of non-stop service to my advantage. My logic is since I have to take multiple flights anyway, I'd like to earn RR credit for them all. So instead of booking the 1-stop connection as offered by the system in a single reservation, I booked the same two outbound flights separately to earn two credits (and also found an unexpected fare difference in my favor!)

5/14:
MDW-SNA
#3331/500 (stops DEN/1 with plane change)
Wanna Get Away $169.30
Total w/taxes & fees $203.20

MDW-DEN-SNA
#3331 Wanna Get Away $68.84 (w/taxes & fees $84.60)
#500 Wanna Get Away $54.88 (w/taxes & fees $69.60)
Total w/taxes & fees $154.20 (savings of $49.00)


While looking to do this for my return on 5/18, I noticed flight #2378 SNA-MDW with one stop in PHX, resuming travel under the same flight number, no change of plane. I'm wondering if it's possible to book two segments of the same flight number on separate reservations to earn credit for both flights? If I only had a carry-on bag, could I check in online as usual for both individual flights and then just get off after the first portion (SNA-PHX) and reboard for the remainder (PHX-MDW)?