At least in the UK, smart meters don't use radio-based time switching as they have their own clocks which are synchronized with their remote system. All command

At least in the UK, smart meters don't use radio-based time switching as they have their own clocks which are synchronized with their remote system. All commands to these smart meters (including the ability to remotely disconnect them) are cryptographically protected to ensure integrity and authenticity, and also have anti-replay protections. Disclaimer: I've worked for a smart metering manufacturer.