Modern theory tells us that the Staunton Gambit against the Dutch Defence (1.d4 f5 2.e4) is now equal or better for Black with best play. But below the top levels, the gambit still sees a lot of play, it's not considered a bad weapon for White! There are plenty of sidelines for White to choose from to try and outfox Black, as well as the tactical mainlines. Moreover, quite a few White players don't want to have to study the interesting positions that come from the mainlines of the Dutch (I play the Stonewall) and so throw out an "Anti-Dutch" sideline, and the Staunton really falls into that category in my opinion (the other common one is 2.Bg5).
So why am I not afraid of the Staunton? Which I'm not; I consider it a great oppurtunity to try and score a win as Black!
Well, it's precisely because it's a sideline! And most White players have to play one of the sidelines in the gambit itself - so come on, these guys are playing sidelines within sidelines, something has to give! How come White players keep playing these sidelines so often? Well, must be because they win with them. Why do they win? Maybe the Black player isn't adequately prepared! So I'm of the mind to spend much, if not most, of the time I spend preparing the Dutch (my main weapon vs. 1.d4, so a huge part of my repertoire) studying these silly Anti-Dutch lines, outpreparing White (who as a d4 player probably spends little to no time looking at the Dutch) and getting equal to superior middlegames to play! That's the idea anyway - anticipating that people often play the 2.Bg5 and 2.e4 ideas, and preparing for them as necessary, and I should be getting results.
To be honest, I've only been playing the Dutch a few months, haven't even studied the Staunton much yet, and yet in 15 minute games I'm getting good positions out of the opening (I don't think I've encountered any particularly dangerous sidelines yet; but when I do I'll hopefully be ready - these are only casual internet 15 minute games anyway).
Anyway, enough - here's a win I scored in a 15 minute Staunton game just now. White played an innocuous line in the Staunton, cashing in as early as move 6 his attack to regain his pawn. But Black gets a very nice position with the two bishop advantage. Then the kings castle opposite sides, but White completely fluffs his attack, and Black has all the time in the world to prepare a routine attack on the White king, himself in no danger, and picks up the point with minimum trouble.
Thanks for reading!