Legality of phone confiions in public high schools in the U.S.?

Searching the phone, is the only one that would be questionable. I had a law clinic case on this, and the JDR court here in Virginia ruled that the content of the phone was inadmissible to determine if the child was delinquent. In loco parentis would apply to stopping the disruption, and does not give the school the right to violate the 4th amendment.