Courtesy Runner In Game ?

[Chess Ref]

Had this come up and partner was pretty adamant we should get an out and a DQ.

F1 gets a single. Coach tells me he's got a courtesy runner for the pitcher. I pull out the line up card and see he has no eligible players.

During the time I'm pulling out the line up card and checking , his player off the bench and F1 switch places.

At this time I tell him that's not allowed. I explain rule to him. He pulls player off the base and sends F1 back out to 1B.

My partner, BU, then comes down the line and is pretty insistent we have an ineligible CR and need to get an out on that.

I hold steady in my thinking and we move on.

So my question is when is a CR and or sub "officially in the game"?

I always handled it as when I write it down and announce it.

Rule 4-6-B states "considered officially in the game when reported to the plate umpire".

What say you ?