Last spring I was watching a HS tournament, the dad sitting on the bench gunning the player yelling out what the velo was on each pitch. He was asked to stop as it was perceived as cheating.
I have seen parents do all sorts of things behind the backstop, mostly dads. Anything from giving signs to yelling out velocity of each pitch for their pitcher. I have ssen in on the college level as well. We had a wife who sat behind the backstop regularly, giving instructions plus demeaning the umpire. It was very embarrassing and the coaches and the team hated it. Could be the reason why he didn't pitch in Omaha.
It may have been unusual to see a mom do this, but I have seen dads do it also, try to run the game from behind the backstop.
I agree with njbb, doesn't matter who did it, it's wrong and uncalled for.
Moms are more and more involved these days, some of it good, some of it not so good, same as dads, uncles, aunts, brothers, sisters, wives. Maybe I did take offense, but I most likely would have posted "parent" instead of mom, because this isn't just a mom thing.
I think what threw me the most was the reply, shut up and take a seat mom.
Boy how many times would I have loved to say that to some dads!