<font face="Verdana, Arial, Helvetica, sans-serif" size="2">Originally posted by Kidz:
Not being able to buy a later flight for the right price, I was wondering if ther's any problem (both Airline policy, and ethically) buying a cheaper fare for an earlier flight with no intention of going then, but to try to go Standby later.</font>
Don't try this on Southwest. They have been wise to this scheme for years, and they will charge you full fare unless you miss your flight by less than 2 hours. Otherwise, as you effectively point out, Southwest could not maintain dramatically different prices for peak hours vs. off-peak hours. (Economists call this "capturing the consumer surplus".)
The fact that other airlines allow this practice is more proof that they just don't know how to run their businesses.