But this is not true.
Because the "legal" miner gets to colaborate more in the long rounds, the ones that are less profitable, while the pool hoppers jump to a new one and stop collaborating. In the more profitable rounds, the pool hoopers get their complete share.
Supposedly you are collaborating in the long rounds because it gets compensated in the short rounds and with time its even. But if some of the miners only collaborate fully in the short runs and only a part collaborate in the long rounds, the less profitables, there is a problem where some are benefiting at the expense of others.
Please point out why another pool's payouts during that time affect the normal BTC Guild user. You quoted one of three scenarios. In the end, the non hoppers make the same BTC/minute whether the hoppers were involved for all of the round, part of the round, or none of the round.
First, the "legal" user does not benefit from having the hoopers in the short runs or in the beggining of the long rounds. Yes, it will make the pool discover rounds quicker, but then the bitcoins have to be divided among more people, so there is no increase in profit from having the hoopers for the "legal" miner. Maybe the only advantage is a reduction on variance, but only maybe because they leave in the long rounds making them longer (Im not really sure about the net result on variance but its irrelevant, the point is that it does not increase the profits for the "legal" miner to have the hoopers).
Then, the shares in the quick rounds are more profitable than the shares in the long rounds. Ideally everybody would want to have luck and get quick rounds. But we know that over time things even out, so "legal" miners assume that they will get an even number of more profitable shares and less profitable shares. But pool hoopers get a bigger number of more profitable shares, while leaving the less profitable shares to the "legal" miners that have to assume its costs alone.
Is that clearer?
EDIT: Its easy to prove that hoopers are taking bitcoins from "legal" miners in other way: Since bitcoins are created at a predictable rate (lets ignore difficulty changes for this), and hoopers make more bitcoins by changing pools (and this can be demostrated easily), it means that there are less bitcoins for the rest. This is because the "legal" miners work more on the less profitable shares (the ones from the long rounds) than the hoopers.