Delta does upgrade medallions on flights to Canada, Mexico, Carribean, Central America and northern South America.

I should have clarified that it was transoceanic(Europe and Asia)

I was told that this is at the discretion of the station manager. I was trying to get out of EZE with 33 open in business and -33 (oversold) in coach. I figured I'm golden, they'll just tell those coach guys to get lost. WRONG! They randomly upgraded from coach into biz (apparently a lot of them weren't even medallion!), and NO nonrevs got on. Sleepinginairports.com is a good website... Be very careful if you ever see a situation like this, there are apparently no rules about coach > biz upgrades, especially internationally.

If a passenger has a confirmed seat on a Domestic or non business elite seat flight they will not leave them at the gate. They will either place that passenger in the first class seat or upgrade a FF and give the coach seat to the passenger. On international flights with business elite they are not normally suppposed to upgrade from coach if oversold. It does however happen and is usually directed from the OCC. One of the considerations is availability of other flights and cost to rebook.

When I am listing for a flight with first class...in the standby section...I see people listed F and FY with priority codes B,D, and F. Then I'm the only nonrev listed S3C. Are these people awaiting an upgrade that already have a coach seat?

I started a thread on this earlier. I got a lot of good responses:
http://www.airlinepilotforums.com/re...dby-delta.html

It so happens that Delta will upgrade some Coach pax to Business/First, if coach is overbooked on those int'l flights. There was a flight w/ an open Business class in which I thought I'd get on, but they ended up moving people from Coach to Business to allow the overbookings to get a seat in coach. I wasn't able to get on that flight.

bump. I'd like to know that answer to this too.

I tried to get the answer from some company pass bureau people and they didn't have an answer for me. I was trying to figure out what people, if any, on the standby list have a seat and if the numbers on the AV column account for any people on the standby list. Anyone? Anyone?

To see who has a seat you have to go to the "show airport standby list" screen to see the actual seats available, standby priority, and seat assignments when cleared. When they start clearing standbys, they'll disappear from the list and show up on the cleared list which will be on the bottom of the airport standby list (bottom of the page).