The obvious danger? Adding stress and the feeling that the employee is not to be trusted.
When I began in my business almost 30 years ago, we had rudimentary technology and office hours were very much fixed. Contrast this with today and millenials are multi tasking from home while monitoring children or having repairmen fix their fridges. They come and go with greater ease but on the other hand are taking calls from Australia late into the evening disrupting the family routine.
I work my own unusual hours in order to more effectively live as a woman part-time and my company knows what I can do. My experience and ability to deliver a good product is what ultimately counts.
I believe this is where the danger lies in trying to measure productivity. I now spend much less time to do a better job because I know where all the pitfalls reside and do not waste time. I will also produce a more cohesive product than someone who has worked only a few years.
This is where technology will not serve the common good and risk turning professions which require much mental energy into assembly line rigor that does not yield positive gains.
I understand the motive but cannot help but vehemently disagree with the approach.
I don't think more Big Brother is the answer.