So far the times that I have flown home on SW my boarding passes were not left at my door with the DME envelope. I have checked my self in at T24 and I have also had EBCI. Yet, I have heard many stories of the BP's being included in the DME package. I don't count on them being left at my door....I get the folks at the RAC counter to print them for me. In fact, last time they asked me if I had already printed my BP's before I even got the chance to ask them to do it.
I have had the BP's left when I have used other airlines.
for the first time in about 4 trips i actually read the DME packet when it arrived while i was waiting for DF to get ready for work, and now toward the back of the booklet, it says that for eligibile flights on 8 specific airlines (i can't remember all 8, i'd have to look at it, but i know SW, Airtran, United, US Air were included), your boarding pass would be printed and dropped off to your room on the morning you check out.
I need to go home and check the exact verbiage, but this was the first time I read that, which answers why some people have their boarding passes on their door in the AM on the day they check out and others have never had that happen. There was no explanation as to what constitutes an "eligible flight", nor was there any instructions as to whether you could find that out ahead of time.
So really, as i'm typing this, i realize it doesn't really necessarily answer anything, since there's no way to know if your flight is "eligible" for you to have your boarding passes printed and delivered to you, until you open the door and they're either there or not. It may make those who were wondering or feeling uncomfortable about the idea of receiving their boarding passes this way more comfortable since it's in the DME booklet that they may be providing this for you.
ETA: I found the booklet, and it says on the Resort Airline Check-In page:
"if you are flying domestically on one of the participating airlines below you are automatically enrolled in this service when you arrive through Disney's Magical Express.
Airtran, American, JetBlue, United, Alaska, Delta, Southwest, US Airways
If your flight is eligible, your boarding pass will be delivered to your room on the morning of your departure. Otherwise, you may pick-up your boarding pass at the Resort Airline Check-In Desk no less than 3 hours prior to your flight.
Guests with a departure time before 8:00AM must check in at the airport.
Some guests may be required to check in at the airport and will be unable to use this service"