I don't think he was aware of what the consequences of his actions were, because if he did, he would refrain from pulling off something so stupid. It's largely pure ignorance combined with a tint of arrogance.

Some people really believe they found ways to remain unnoticed while doing illegal things, and it time on time again proves that you can't remain unnoticed for a long period of time, especially not when it comes to mining.

The peaks in energy consumption can be measured quite easily, and in case of weird usage patterns you can expect a visit from both the police and the company providing you your energy.