Ms Ross, a Glasgow primary teacher, said the "bottom line" was that some young people should not be in mainstream classes if they affected the education of others and urged ministers to choose their top priority - attainment or inclusion?
It was more difficult than ever to protect the majority of pupils by excluding troublemakers because schools are looking over their shoulders at local authorities who are looking over their shoulders at the Executive and the "legal eagles".
"Our schools are on the verge of being legal minefields and that is in the interests of no one except lawyers," she told delegates.
Ms Ross said EIS members sometimes confused discipline and social inclusion issues. "Discipline problems are often caused not by those who have been included but by those who have always been in mainstream education," she said.
The solution to indiscipline lay partly in early intervention and in strategies such as Glasgow's nurture classes, which were threatened through lack of funds. "Staff had been specially trained to deal with the behaviour posed by the children in the nurture groups. Parents were involved and the children spent 80 per cent of the school day in this special provision.
Another outcome was that the children in mainstream P1 and P2 classes were able to make more progress than in previous years," Ms Ross said.
Projects like this needed sustained funding, a major factor in improving discipline and including more pupils in mainstream. Teachers and support staff needed training. "Social inclusion cannot come on the cheap," Ms Ross said.
She accused one authority of forcing children out of special schools. "They are not closing the school, they are just not admitting new pupils - a slow death - and what price those parents' choice?" Ms Ross asked.