There was a great loophole, decades ago. You had an effective 2 month window to renew an existing TV license, or get a new one. So a new housemate could pay for a new license at the same address, every 14 months, paying in cash at the nearest post office. New name every time, 12 months plus 2 months of slack, then another mystery housemate pays for another new license, that covers the same address.
They got rid of that loophole though.