Originally Posted by Xiaotung

I think we should take it easy. You could argue that people coming on Flyertalk is to be cheap. I have once myself got an NZ agent at LAX to thru check my bags onto SYD on a separate Seat Only ticket and got away with it. Do I consider myself cheap? Maybe, but I don't see anything wrong with it as long as you are prepared to cop the excess baggage fee should it not work out. And I was.

In OP's case, I wouldn't do it because during a domestic "connection", you will be asked to re-check in your bag and that's potentially where you could be charged.