I find this not a very satisfactory reply. The auditor could have access to knowledge about physical resources consumed (electrical usage, heat generated). An attempt to trick the auditor (whatever that means) would require a strictly larger search of the solution space, requiring more computational energy expended.

It's not really clear what you mean by 'trick the auditor' anyway. The auditor would have access to logs of the computational substrate running the AGI, portions of which could be inspected without summation. Even if the AGI had such capability, it would have evolved such trickery, and that development would be observable.