I think that a good part of the alleged saving is a false one. Of course my experience is limited to the passenger side, and a lot of this comes into play with reaccommodation.

In the past, an endorsement to another carrier was handled by printing out flight coupons (or tearing them out) and attaching them to the BPs or itin for the other carrier's flight. It was simple and painless, and someone in a back room somewhere handled the paper tix and revenue accounting after the fact.

Today, my experience in getting endorsed to another carrier is usually pretty complex. It involves either multiple trips between counters, and almost always a call to the internal Helpdesk. I just have a hard time seeing the savings when a frazzled gate agent is spending 20 minutes trying to do something he/she doesn't understand, while wasting 10 minutes of some Helpdesk guy's time trying to get things in order.

The last time CO sent me to DL, they reissued the e-ticket, printed me a DL BP that said "PAPER" but told me it was really electronic, spent 20 minutes with the Helpdesk, finaly printed out the e-ticket receipt, highlighted the ticket number, told me to go to DL with that (I was skeptical). Got two agents at the Crown Room to look at it, finally got on with their support, found the e-ticket coupon, manually keyed it in to associate with my record, and printed out an ETKT boarding pass. And these guys are partners! I've had similar experiences going US --> UA, CO --> NW, etc.

Oh yeah, we're saving money with those e-tickets.

Sometimes a paper ticket and a stapler is just easier for both sides.