I can't speak for every away fan, but when I go to Oriel I stand on the terrace. I can't imagine paying to sit in the stand because sitting at football isn't my thing, especially at an away game. Many fans don't want to split up their vocal groups so would rather stay out on the terrace even though they can't see all of the pitch and may get wet/cold as a result.
Many more just choose not to go. It will be interesting to see our crowds at Oriel in the two trips we have in the early season. Some will choose to go to the Presidents cup and some to the league game, though most refuse to travel to Oriel in any circumstance.