scorer's keeping track of Delay of game warnings?

Last night I had a Frosh Girls game and gave the visiting team a delay warning for knocking the ball away after a made basket. The scorer that we had was a student who was unsure what to do. My question is how are the scorer's supposed to keep track of the warning's given or is the responsibility of the officials to remember the warnings that were given?

I just had the scorer mark the book at the bottom of the visiting teams page in the score book with something that I would remember what it was for.

Thanks for the responses