We've known for a while it works. My question is, who's responsibility is it to trying prevent this? Pool operators obviously don't have a big interest in keeping out computing power and I can't blame them. Though if it's just a matter of way the pool is being operated then, who else can? Soloing is an option, but not a great option for everyone. And lastly, is this really an issue that exist and can we detect this in any way with proof? The talks of it being possible has been around for a long time now.
You can probably detect it statistically from the distribution of block times for the pool. If there is pool hopping then there should be a longer tail. In the extreme case (which obviously doesn't happen) once a block takes too long everyone hops out and the block never finishes (infinite block time). I don't know for sure there is enough data to make a strong statistical inference on this, but I would guess there is.
I would bet every BTC I own that there is pool hopping happening on at a fairly large scale, and people have automated it. And I agree that the way things are structured now the pools don't have a huge incentive to do anything about it. The best thing to do is avoid pools without good defenses.
