Originally Posted by corporate-wage-slave

It may even work well for domestic flights on bank holiday weekends, around Christmas and around Easter. Though there is usually some availability somewhere, it may be the very late LCY or LGW flight. Cash fares during civilised hours could be £250 plus, even though barely a seat is sold: BA knows the flights will fill up at some point and won't be in a rush to offer cheap seats. GPR to the rescue!

Note that GPRs can be cancelled without fee, should mainstream availability show up.