I vote for educating this teacher - and her supervisors - about the fact that your son has a disability. Again. Just because his disability is not as obvious as the child in a wheelchair or with a white cane doesn't mean he doesn't have one. This WILL get exhausting if you have to keep going through the same thing over and over. From what you have posted the common denominator is teachers who don't understand this.
I can't remember if he has an IEP or a 504 but I think it may really be time to call a team meeting and get everyone involved to understand that this CAN NOT continue to happen over and over. No you don't need to apologize. And I am afraid that it already is a bigger issue - address it now or it will keep coming up over and over again.
{hugs}
