If they are not aware, then the employee is being badly managed, or maybe not managed at all.

Yes, which is why we are probably going to see a huge crackdown on remote work where everyone's output is carefully reviewed and if you have a slow week you'll be audited to check your output matched the 40 hours work expected.

The assholes like the OP author are going to make remote work suck for everyone.

Based on some brief Reddit scanning on overemployment, most people don’t seem to reveal that they are working 2(let alone 3) jobs.