My cousin worked for many years as a special education teacher in a small Oregon district.  He finally left because he was, most of the time, the district's only qualified special-ed person.  There was often no support or alternate ways to meet the needs of students.  He was asked to do more than he could do.  

I also see this issue through my service on the Teacher Standards and Practices Commission, where we consider both requirements for special ed teachers and, sometimes, the consequences when teachers are asked to do more than they can do.

What matters is not what the law requires, because the law is an abstraction.  What matters is what people are capable of doing on the ground.   Governments will get the results that are possible, not the results that are theoretically correct.  

If the government's reaction to unmanageable situations is to issue orders that cannot be obeyed, it is time to revisit the underlying issues and how society has chosen to resolve them.