Originally Posted by
IADCAflyer
Its an attempt by them to get you to move off your schedule which frees up a seat for them. Most people ignore it, but sometimes the passenger does find value in it.
There are plenty of folks who picked a given flight (or even a travel day) because it was cheaper, but wouldn't mind an earlier/later flight (or an extra day). And of course, once they're offering $300, if you have the next day off work (e.g. a Saturday flight and you've got Sunday/Monday off), there's a good chance that $300 might cover another night in a hotel?