i absolutely agree, don't do it.
but, i don't agree w/the arguments. everyone is saying if you miss your first leg, your itinerary will be canceled. i don't believe that's true. for instance, when you miss that first leg, you can go same day standby *after* your scheduled flight and you will be fine. so they can't cancel your ticket until i think midnight (not sure what time zone) of the day of the first flight you missed.
now maybe they won't let you on the eugene flight still because they'll see that you didn't take the first leg. but you won't lose your ticket. i suppose if eugene wouldn't let you on, you could drive to pdx and start there doing a same day later flight standby???
i still say don't do it, but i want to understand the rules a little better here, cuz it feels like something is missing.