boundary plane question

[kmw]

this happened last night in a hs jv boys game. Ball is being put in play in frontcourt on sideline opposite table. Defense reaches across plane and puts hand on the chest of player with ball. My partner calls a technical... coach complains that it should be a warning.. rule book states that if there is contact with the thrower but no contact with ball- it should be an intentional personal foul. Any thoughts? does reaching out and touching -not pushing- constitute the personal foul? It was an interesting game last night- definitely a learning experience- power failure 5x, the last one being at the 3 min mark in second period. Power comes back on and game mngmt decides with coaches approval to play the last three minutes- skip halftime and play 3 & 4.