The issue of giving the passenger who misses the flight 300USD is very simple logic,it is also an IATA regulation for overbooked flights. I also once worked with an aviation firm so i know what i am saying
Overbooking is not a negative in commercial aviation but rather a plus.
I will not get involved in the calculus of how bookings are managed but just challenge yourself with the following questions
1. Which is the larger cost,10 empty seats (400USD)when you try to control bookings or refund 5 guys 300USD on an overbooked flight.
2. If you give the customer 300USD and a flight the next day,you have a happy customer who thinks he has gained a 'free 300USD' and hotel room.
3. If you gaurantee the guys a flight the next day,you will bump of a closely similar new group the next and so on till you get to the point where there is space in the plane.
If you find you are sustaining this pattern often,you are in business
Finally ask yourself,why would a carrier overbook in the first place?
I am a general consultant,specializing in all areas.
Meru Holiness