Hi, i am an ex school board member and i agree with searches but only with probable cause.IE if a child is acting strangely and has red eyes etc. However i think the child`s parents should be notified in the first instance and questioned over the phone or in person.
By involving the parent you would get a good indication of weather you were barking up the wrong tree or not.
A call to the police would be a good idea to get information on your rights as a searcher and also the rights of the child and parents.
MAKE SURE YOU DO YOUR RESEARCH before approaching any child or you could end up in court.
Good luck