The fact that Fielder won't be missing any time on the field is huge, and it may be because he waited until after the game to take out his frustrations on the Dodgers reliever. Had Fielder charged the mound during the game, you'd think that both players would've been suspended. I'm sure Prince (and the Brewers) will happily pay the fine and move on. Still, it's a little alarming how many times this year the Brewers have found themselves in the middle of beanball wars -- players from both Pittsburgh and St. Louis have made it known that they strongly dislike the Brewers, and there's been multiple promises for retribution through the media (specifically, Ryan Braun and Mike Cameron).
One thing I can say -- it's a good thing Ken Macha doesn't believe in intentionally putting guys on base and partaking in beanball wars, otherwise there would be a slew of Milwaukee players serving suspensions this year. It's something I couldn't say about Ned Yost (who once put Seth McClung in the game for the sole purpose of hitting Albert Pujols, knowing full well that McClung would get tossed after one pitch, so he had another pitcher warming in the bullpen).
The Journal-Sentinel has the story on the fines.