Another reference for OP
https://www.bridges4kids.org/AA/aaq7.html
Ask the Advocate with Tricia Luker
Question: May a district require parents of students with disabilities to accompany them on field trips when non-disabled students are permitted to attend unaccompanied?
Answer: NO. A district may invite a parent to accompany a student with a disability on a field trip. But it cannot make the parent's presence mandatory when a similar obligation is not imposed upon the parents of non-disabled students. A district which requires only students with disabilities to be accompanied by a parent on a field trip discriminates on the basis of disability in violation of 34 C.F.R. 104.4(b)(iv). See San Saba (TX) Indep. Sch. Distr., 25 IDELR 755 (OCR 1996) (district could not condition the participation of a student with spastic dysplegia/palsied left hand in a rock climbing expedition on her father's accompanying her.)
As a related concern, requiring a parent to accompany a student with a disability can be a denial of FAPE. This was the opinion expressed by OCR in Ventura (CA) Unified School District, 17 EHLR 854 (OCR 1991). In that Letter of Finding a parent complained that while the student was disabled from a broken leg, the student's teacher made his participation on class field trips conditional upon the parent accompanying him. While OCR's investigation failed to produce evidence to support the parent's allegations, OCR stated that if such a requirement had been imposed, it would "likely have violate[d] the Section 504 regulations. If disabled students need related aids or services to participate in the school's program, such services must be provided by the school, not the parent."