Yes, all subs must be reported by the 10 second warning signal during the time out. If it is a game where the numbers of the players are not being kept, you can get away with them not reporting, but that can turn into a bad habit. I had a VERY instructional league where coahes were just parents who will still be learning the rules 20 seasons from now, one or two players would report and then at the last second one more player would come sprinting off the bench as I beckoned them in. Pretty soon it got to a point where we had a dead ball, my partner hands the ball to the white team and a blue player comes wandering onto the court. I stopped play and walked towards her saying, "no, you are supposed to check in at the table first, you have to go back". The coach was a little upset or confused as he thought it was ok to just holler over to the scorekeeper "hey I got a sub next dead ball". The scorekeeper would say ok. but most of the time the players would be at the table anyway and the scorekeeper would remember to buzz for them. Maybe the players are watching too much hockey.
