Some employers insist on excessive and aggressive control on their employees , by installing cameras in offices.

i think camera installation will not help improve the productivity of the employees. rather you can have periodically performance appraisal system.  big companies normally periodically check the performance of the employee by reviewing the completion of the task given to them, how much time was taken and the standard of the work done. also how much responsibilities given to the employee. how effeciently the employee manage those responsibilites.

This is NOT at all a good practice; micro management to control employees does not work. This is not a school, the management is to treat staff with trust and respect.

For creative works and intellectual people, the control by installing camera is a worse idea.