Hi Graphic D,
My daughter didn't get an official acceptance before the poster review - just the admissions rep asking her for another major - saying that she wanted to be able to offer her admission if GD fell through. She said the academic review and poster review were completely independent of each other. Her acceptance on 12/26 was into the GD pre-major, after both GD had reviewed her poster and admissions had done the academic review.
My understanding is that the poster is very important, and that the focus is more on the explanation of the poster than the skill/design itself. Bill Kelly (dept head at the time) actually said jokingly that they should just have students submit the explanation and not bother with the poster. They want to see that you have the thought process to come up with a creative idea and then turn it into something tangible.
Here's the way it was in 2008 - very competitive, admitting only about 25 freshman a year into the "pre-design" program (less than 10% of those who applied), and a similar number of sophomores. From that 50 or so students, 2 years later, they accepted only 17 into the actual graphic design major. My daughter did not make the cut into the junior year, and was totally devastated - but she ended up double majoring in Integrative Arts (with concentrations in GD and Photography) and Communications - Advertising/PR
track. She graduated in May and just landed a great job in DC that will utilize some of her GD training - so it ended up turning out perfectly. She had an amazing 4 years - the best part being THON!
Good luck to your daughter!