IEPs are for deviations from the academic curricula, not for physical accomodations. Kids in wheelchairs do not require IEPs - the gym issue can be handled by a doctor's note, I believe. "Special services" in this context are academic deviations, not physical accomodations.
BTW - Your hostile "idiot mom" comment says more about your attitude toward the issue, not the Mother's.
That could be true--I've heard countless horror stories of parents who refuse to get an IEP because of the stigma attached that it means their child is "retarded." Of course, there are plenty of horror stories on the other side as well.
My understanding is that if the school needs to make some sort of accomodation based on a disability, an IEP is needed. In your example, a wheelchair, the school doesn't need to make any accomodations (outside of things already covered by the ADA), whereas in this instance there would need to be significant modifications because of the presence of a dog in the classroom.
That being said, I do think the mom is being a bit of a prima donna.
You are wrong. IEPs also handle physical accomodations. Kids in wheelchair do require an IEP.