I have been to games in three stadiums, Seattle (a lot), Oakland (a few), and Phoenix (once). A common element across all those experiences is that very little information about the outcome of a play is announced to the crowd.

For example, if the batter walks, he just drops his gear and goes to first base and then the PA announces the next guy up. This may not be a big deal for common plays like a walk, but when something like a balk happens, the umpire makes a hand signal that you may not see if you're not looking at them, and the runner moves up a base. There is no announcement of what just happened, although the scoreboard may show: "Scoring decision: balk". I was recently at a game where a manager was ejected, and there was nothing said to the crowd about the fact, you just had to be watching the umpire's gestures to get it.

I did notice recently that when a replay challenge is decided, one of the umpires announces the decision to the crowd. But, basically nothing else is announced in the games I've been to.

I contrast this with my experience at basketball games, where many things are announced: from the name of the player that made a shot to who committed a foul.

Personally, I think attending a baseball game would be more interesting for the casual fan if more things were explained over the PA, so I wonder why they don't do it. Is this done in the many other stadiums I haven't been to? If nobody does it, is there a reasaon why?