I really don't understand why sec 18 wouldn't be the most desireable seats in the OOD, aside from the misc lux seats of course.
Sec. 6 is pretty sweet, but the tuck factor is over the top. The old people will literally tell you to not stand up before you even sit in your seat. (true story)
I've never sat in sec. 18, but I would guess if you got above row 5 or 6 the standing students might obstruct the view depending on which side of the section you're on and if you wanted to stand yourself. In addition to mine, they told me row 6, 7, and 11 had open seats in sec. 18. Also some in row 2 in sec. 17 in case anyone wants to move down and they are still open.
For people waiting on the call, just go ahead and call or go up there. I've always had luck doing that instead of waiting around for them to call even though it somehow worked out this time.