Think it's common that if both of you would get in line, and if the friends leaves and they are gone for too long, then they lose their spot. To have the friend come before opening is no different than letting 30 of your friends cut in line, and that's what it is, cutting in line.
I was annoyed with what I saw on the xbox 360 launch. I was closer to the end of the line, we all counted the people in line to compare to what the store had, so many of us waited based on that.
Then 5 hours later, an hour before opening, suddenly a car of 5 people pull up and get in the front. Word spread they were there first, but they were gone way too long, as to us, they were never there.
And now that threw off the whole count, making the 5 hour wait pointless to some. Thank goodness there was leeway with the count as not everyone in line was there to buy. I guess they went and partied somewhere nice and comfortable for the 5+ hours as they ditched their spot, and coming back they stole units from someone waiting in the freezing cold the whole time the right way.