I have no problem with advising students to approach things with an open mind and study them carefully, but the fact that this one issue was singled out reflects on the motives of those who insisted upon the sticker in the first place.
If the disclaimer was in the front of the text, stating "This material should be approached with an open mind, studied carefully, and critically considered," I'd be fine with it, because it wouldn't be singling any particular concepts out due to religious reasons.
As a graduate of the Cobb County school system, my personal experience was that evolution was barely covered. I remember that in my 8th grade science class, a student asked the teacher why we were skipping a particular chapter, and her reply was something along the lines of "It's a sensitive issue and we don't want to offend anyone."
Rather than disregarding evolution or making it seem "forbidden" as a concept, I think it should be presented as one theory among many, and students can draw their own conclusions based upon their personal beliefs and values. If a parent feels very strongly about Creationism, he/she can share these beliefs with his/her child in the home.
We see the world as "we" are, not as "it" is; because it is the "I" behind the "eye" that does the seeing.