You cannot really prevent those kinds of cheats. Even if you use the most insidious spyware a coach can advice the interviewee from a different device.
The only way to prevent those kind of scams is to put all employees in probation for the first months of work and fire them if they don't perform, like it's common in the UK.
The only way to prevent those kind of scams is to put all employees in probation for the first months of work and fire them if they don't perform, like it's common in the UK.