As far as i understood it at the time they where strict classical rules. The hand that touches the clock is the one to move a piece. Touching a piece means you must move that piece. Illegal moves are an automatic forfeit (i always presumed because they are undistinguishable from trying to cheat).

Its possible that tournaments are setup with different rules but i never really had the experience to find out. Considering kids there is also a good chance my opponent would have just lied, queen was already moved to a now legal spot.