Question from a game a couple of weeks ago

I've been meaning to ask this question but just haven't gotten around to it. In the game where Pete challenged the spot 3 different times (was that the Rams game?), did we ever find out why he lost the 3rd challenge? Collinsworth or whoever made the comment that it might be that you don't get credit for stretching the ball out if you're going perpendicular to the sideline, only if you are moving along the sideline.

That would seem like a stupid rule to me but was that what it was? Or did the refs just suck? My dad's theory was that the refs didn't want to have 3 spots overturned on replay. Figured it would make them look bad.

When I saw the play, I thought that spot was more clear cut than the second one, which I was surprised they overturned. Supposedly there was an aerial view that showed the second one better but I had stepped out of the room when they showed it.

Anyway, none of that last part really matters, it's the rule or potential rule that I'm curious about.

When a player goes out of bounds, the ball is placed at the spot where the ball crossed the out of bounds line. On that play, the ball was stretched toward the first down marker, but after it had already crossed the out of bounds line.

Thank you.