I would think that with SNA being a "premium" airport, it may be easier to talk one's way onto a LAX flight than vice versa-- using the rationale that average SNA fares are higher than comparable LAX fares.

If reldude is booked on the 5:10pm EWR-SNA flight, I would say his chances of being bumped are extremely high--- the flight doesn't even show full fare F seats to sell. Know that there is a 4:55pm EWR-IAH flight with connections to ONT-- so CO may very well start bumping early (i.e. 40 min. before departure) to get people onto this connection. So, make sure you get to the airport extra extra early-- I'd say even 90 min. early at the gate if you can-- and have some reroute options in mind. Later EWR-LAX flights don't come up with seats to sell