Booking round trip vs separate flights
Take the difference you save and double-down with it at the tables...
The airlines do it all the time... at least USAirways does...
I may not have as many "miles" as George Clooney's character is Up In The Air, but I can remember several occasions when either my depart or arrival flight was cancelled and USAir booked me (or offered to book me) on another carrier... not a sister or affiliated airline, but a competetitor.
And, yes, I retained the full USAir "dividend miles".
One time, 10+ years ago, they offered to pay for a train... which, may have been fine for European travel, but train travel down the US mid-Atlantic is suspect at best.
BTW, it's called throwaway ticketing.