Let me start by saying that I know that there is a no-waiver policy for confirming a flight change even same day. What I have been able to do in the past is have the agent at the check-in counter confirm me on an earlier flight if there is space available. I always assumed that the airport could change your flight without charging. Last friday I was trying to get out of LAS a couple hours early and when I checked in, I asked about standby for the earlier flight. The conversation:

Agent - "It looks good, as a matter of fact, I just put someone on that flight a few minutes ago".

Me - "Can you just put me on the flight then?".

Agent - "I could, but I'd have to charge you $100"

Of course, I tried to confirm whether this was a new policy or not, but she seemed a bit confused as to what I was asking. In the end, the flight had 1 standby who cleared and it was not me. I should have just ponied up the $100, but I mistakenly thought that things looked good based on the original agents comments.

Has anyone been successful in getting on an earlier flight at the airport without being charged $100 or sweating out the standby list?