Chris Welford's Answer:
It's quite understandable that your staff member should feel this way but the problem lies in the measurement of inputs over outputs.
Much of our thinking in relation to the world of work is dominated by the machine metaphor, where we attach undue importance to consistency, conformity and control. In the end it's what's achieved that counts, not the slavish adherence to a system or timetable.
As customers we know this. Who cares if the phone is always answered on the third ring if the company representative rarely resolves our issues first time and we end up being passed through an organisational process of Byzantine complexity?
So before we run to HR and ask them to adopt the role of corporate police officer, we need to step back and consider what is being accomplished. It's quite possible that objectives are being met and targets being reached with non-standard work patterns and if your performance management system doesn't recognise this, it's almost certainly overdue a re-vamp!