Courtesy runners

[TERRY1]

I understand courtesy runners ok but had a team yesterday that used the same runner for both pitcher and catcher. I know this player would be an illegal sub. and in rule
3-1-4-a of FED book it "may be discovered by umpire" I had always been lead to belive it was the other teams job to catch this. Should I as a bu call this when I see it and call an out and restick to dug out?

[SamNVa]

Terry,

That's what the rule says, so that's what you should do. It may seem harsh to a team who does this by mistake or out of ignorance, but they'll learn the rule alot quicker when it's enforced. And for the team trying to pull a fast one, well they get just what they deserve.

--Sam