Of course it isn't an accusation. I'd hardly be using the pool if I thought it was stealing. I am of the opinion that openness is the best way to go, regardless of underlying honesty. This is not an uncommon opinion.
Your second paragraph. I don't know what you're trying to say. You can't state any of that as fact, you don't have a clue what happens after your shares get sent to the mine and you obviously can't monitor all the other miners using it. I agree that that's almost certainly the case, I just don't see why you're writing it.
The reason that
I think that it sounds like an
accusation is that you used the word "siphoning" when referring to bitcoins from the pool. BTCMine and no other pool that I have tried siphons anything. Use deepbit for an example. Set the window to five minutes and you will see your hash rate drop way below what your miner reports and other times be way above what the miner reports. It is just a matter of when the miner submits finished shares and the sampling window. There will always be a slight average of less than your miner reports because of the work that is dropped from either a stale share submitted or dropping current work when long polling suggests getting new work. As far as payouts, pretty much all pools payout to the bit cent, but the remainder is left in your pool account and not "siphoned". It isn't like the banks where they use special rounding at the cent level [round to even ... 2.025 will round to 2.02 and 2.035 will round to 2.04].
As far as stating with certainty, sure I can. I use Phoenix 1.47 (haven't gone to 1.48 yet) and I can simply look at the number of shares on the miner page of BTCMine for that miner and then run the client and after several hours [or days], check the number of shares reported by the client as accepted and compare to the value from the BTCMine miner page minus the value I started at. With deepbit.net it is even easier, because you can simply hit reset counters and then both the miner and the pool start counting at 0 (personally, I like seeing the life long submissions for a given miner). With Phoenix, I have never seen a missing share. Using the windows gui miner, I have noticed drift, which is why I started using Phoenix. So, yes, you can tell with certainty.