>It's really unfortunate that some things end up becoming a debate. I prefer science. There is plenty of science involved in reading levels of text. There is Flesch-Kincaid grade level scoring built into MS Word.
>
>"The amount must be greater than or equal to zero." Reading level 4.8
>
>"The amount must not be negative." Reading level 7.6
>
>Clearly the second sentence is for a more sophisticated audience by almost 3 grade levels.

I think most of our users will at least have high school diploma, so they'll understand what negative means :)