Somewhat OT, but the puddle jumpers out of DEN to GUC, MJT, etc. are not so much oversold, but may be weight restricted, causing essentially an oversold situation. Any summertime flight I've ever taken from DEN-GUC (dash-8, 37 seats) has been weight restricted, sometimes all the way down to 20 seats, and perhaps 28 have been sold. This results in frequent bumps, whether voluntary or otherwise. The remedy (outside of the free ticket you're given) is usually putting you on a later evening flight when it cools down, or first thing (6am) the next morning before it heats up.
FYI - huge post on this topic (to some extent) in UA MP forum dealing with minors who were IDB'd from a DEN-MTJ flight earlier this summer. Talks about the density altitude calculations and weight restrictions in a few places. No link sorry.