Mainstreaming is normally used in reference to a student whose home base is a special classroom, but who leaves for assigned classes in regular ed settings. In inclusive schools the student's home is the regular ed classroom. In a fully inclusive school all academic and support services are received by the student in the regular classroom. My child has a teaching assistant and is now in a regular classroom full time.
Inclusion is more than the site where services are delivered.
We have seen students with disabilities in regular classes where they are more isolated then they would be in a separate school. If the child is separated from others and completely shadowed by the aide, then you have a situation of public isolation that may be more damaging to the child, and to the other children's perception of persons with disabilities, then more restrictive settings. Inclusion is a belief system that must be at least accepted, if not embraced, by the entire school . The IDEA does state that children with special education needs are required to be educated in regular classes to the maximum extent possible. The 1997 Amendments to IDEA reinforce and strengthen the intent of law, which is to educate most children with disabilities in regular classes.