I'm not claiming they're mining on a large scale, I'm just saying that the most plausible scenario for removing chips from the tray is to mine with those chips, After all, that's what they're designed for.
Haha yes, I agree.

Just wanted to point out that "only because some chips are missing", we can't conclude that they are running a full blown mining operation right now that generates significant profit. But I think you got that.