Thanks for the all "got your back" feedback. I'm headed out to have my chat with her. My husband thinks it will simply be the first polite warning shot before we have to go to the principal with it, but I'll start with the teacher first in hopes of resolving it there.
And I think my approach will be that as a mother of any child, I'd be concerned about using as a punishment the removal of a student from appropriate learning time and activities - but as a mother of a child with an IEP in place to address his disabilities, I am compelled to advocate on his behalf that the IEP guidelines be respected and utilized.