Is this collusion?

First of all - no offense taken. But you should go back and re-read my post. I said I know most of my employees well enough that I would be able to tell if they were lying. And I have no doubts that the reverse is true as well. Obviously this is not absolute. On top of that, in our business, integrity is such a high priority that a breach of trust on any level would have the capability to have a very significant impact on the business. My point was that in our situation, if one of us thought another was cheating (very very unlikely), any of us would have no problem just coming out and confronting it. And I am confident that the truth would be told. It is a shame that OP's business environment is different in this area.