OK so quick summary of why i ask the above ?

(1) 1/2011 my friends and i fly from washington national to steamboat colorado for some fun on the slopes. on the way back home, specifically fron den - iad, they're oversold and i am given a $400 voucher and fly out the next day. f9 covers meals and lodging.

(2) 10/2011, i use that voucher and pay a little extra for a rt routing from washington national to lax no problems....but the best part is that before i sit down in the lounge for predeparture crazyness, the announcement comes up....that they need volunteers........and i accept, giving my seat up and get a $300 voucher. i am on a roll and my parents give me the nickname, "BUMPER" so i call my parents back and tell them they are now going to be called bumperdad and bumermom. anyways, i eventually get to lax about 3 hrs later than originally planned. ^

(3) this january, same friends from (1) above are going to vail colorado. well actually we will meet at denver and all carpool in a minivan to vail for some epic skiing. on 1/18/2011 i fly from washington natl to denver at 845am. for the return i go on 1/22 my routing is denver - madison (@ 313pm) then madison/wi to washington national (@ 705pm)

sooo my question is what are the chances of needing seats for preferably the return portion of my trip? i sure could use another $300 (minimum i am hoping) for giving up my seat!

thaaaaaaaaans for any input!