I did see that WN said they will give you a refund, but I hadn't seen it mentioned on any of the shows yet. Did my Tivo miss one? Gasp.
In a way, I think it's like rebates. People see the price (minus rebate), and buy an item, and forget to send it in. I doubt that more than 10% of people would actually send it in and get their money back.
I'd rarely think than an airline is going to be 100% full. However, after watching the Airline show, it does appear that they stuff them sardines in quite frequently.
It does seem pretty bad that people who have a time sensitive issue (cruises, funerals) get bumped and have pretty lousy compensation.