It may be that some people are lying, but it also may be that ignorance caused by that the lack of complete transparency and auditability feeds suspicion. You can't expect people to examine the source code to know how it works especially when this is (or should be) a simple accounting matter for your system to report.

Would it be possible to add more detail to the explorer for an exchanged coin transaction through it's entire life from mined coin to final coin, http://www.zpool.ca/explorer/ORB?height=2271808? i.e. the detail page not only shows the block mined (as it does now), but also the total mined coin in the block, and your share. AND most importantly the details about how the mined coin was exchanged: your coin was sent to exchange "x", the total coins exchanged in that exchange transaction was "y", and your share of those exchanged coins is "z", and the exchange fee. Basically I want to be able to see the full accounting from start to end: "A" coins mined - "B" fees (detail of each fee including pool fee) = "C" net coins mined => "C" net coins mined * "D" exchange rate - "E" fee (detail of each fee including exchange fee) = "F" final exchanged coin. The sum of all "F" values should exactly equal the account balance. If it doesn't, then more detail need to be added so that anyone can see the full calculation.

Whether this information can be attained through some other means is not relevant. The pool has all this information and it breeds suspicion if the information is not easy to see. If you can make these details easily available, and there is no errors, then you would alleviate 99% of everyone's suspicion.