In my opinion the airline must compensate me for flight delay or cancellation, even due to weather, if I see the delay and I can identify available alternate flights that will get around the delay and the airline refused to change my reservation to the new flights without extra charge.

In one actual case I got to Boston to do BOS ORD HNL and saw that the BOS ORD leg was delayed. I asked on the spot to change the routing to BOS DIA HNL and they refused. Getting to ORD, the airline had another chance to fix the problem by putting me on the next ORD HNL flight ahead of other standbys but they refused that. They eventually put me on another airline. They did give me some vouchers when I wrote a few weeks later although less than what someone bumped would have gotten, and they did give me miles for the alternate flight on the other airline.

Travel tips:
http://members.aol.com/ajaynejr/travel.htm

Incidentally my original ORD HNL flight was a one stop in DIA and my first chosen rerouting would have me boarding that same flight at DIA.

I didn't think fast enough to pull out my father's premier card (I have the same name) to get ahead of the other standbys at ORD.