Any restraint of liberty MUST be within legal guidelines, in loco parentis is not a license to do what was done nor exile a student to the closet for 8 hours, as an example.
Using duct tape is excessive and deserves censure, but not a kidnapping charge. What kind of little monster was the child? How many times had "appropriate" discipline failed?
C
all the parents? What happens when they do nothing? What about the other kids in the classroom which this child presumably vacated after disruptive behavior? Do they deserve to have their educational opportunities eliminated by one spoiled brat?
I would like to see a policy wherein parents with misbehaving little monsters were told "Get a private tutor or school The education is still mandatory, but your failure to instill even a tiny a modicum of respect means the heathen is no longer permitted in the public school system. Failure to see to said education will see you charged with neglect."
If parents faced the real prospect of being forced to cough up a few thousand dollars every year or make their "darling child" behave in school, they might decide to teach the tykes manners.