I am in a school psychology graduate program and the issue of cultural biases on tests is discussed often. In the field of psychometrics, bias means that the test predicts performance on some criterion differently for one group than for another. If this happens then a test is statistically biased. All of the modern common cognitive tests currently in use are not statistically biased [Brown, R.T., Reynolds, C.R. and Whitaker, J.S. (1999). Bias in mental testing since Bias in mental testing. School psychology quarterly, 14(3), 208-238.]

While tests are not biased many of them are unfair in that they contain culturally loaded questions. Even with the unfairness they do not show statistical bias. It is a distinction that seems to be only semantics for those outside psychology, but they are really two different things. It is good that bias has been removed, but the current question is how to remove culturally loaded questions while still measuring the desired construct.

Actually, IDEA and a right to a free and appropriate public education only apply to students who qualify for special education. Regular kids who don't have any disability that qualified them for special ed have no protection. I just had a special ed law class this summer, where this point was specifically brought up.

Different states have various laws about what schools can ask parents to provide for their child at school. Some let schools ask for each child to bring basic school supplies, while others aren't allowed to ask for anything. Therefore, for regular education kids the "freeness" of the education may vary, but there is no requirement for it to be appropriate.

As for the parent's experience with school districts, it all depends on where you live. There are some general federal laws that are attached to money and apply to all states, but each state has their own interpretation and different laws. Each district has their own interpretation and policies, and each school principal may enforce the policies differently. In short, there is a lot of variation even within a single city. This is one of the problems with America's school system. We don't give local control of medical care or the practice of law to the general public. They are regulated at least at a state level with people who are supposed to be knowledgeable about the profession.