You are a programmer. You write a program. You put it out into production. A week later something doesn't work right.

But you are not in. Nobody knows where you are. Nobody knows how to get hold of you. Whatever broke is important. Things that need to get done - that people are relying on getting done - are not.

And this is a very visible failure.

Massive overtime is a morale and productivity killer. I agree. Being able to choose your own schedule is a huge morale boost. Absolutely. And motivated developers will get more done when they have that flexibility.

But what is motivating these managers is not just the desire to be obstinant control freaks. It is the observation that when people work together, and need to interact together, having them not mutually available while they are working is itself a morale and productivity killer. And most workers do not have the flexibility that people in IT do to do their work when they want. Secretaries need to be around when people will call. Sales staff need to be around when prospects can be reached. Lawyers need to be around when people have questions on contracts, negotiations are happening, etc. Support staff need to be around when people need support. And so on.

Most of these jobs require knowledge just like IT. In fact quite a few of these jobs require substantially more knowledge than IT - as is evidenced by the fact that people can (and do) get into IT without a specific education while people do not (for instance) become doctors or lawyers without a heck of a lot of training. Or stay as such without constantly staying abreast of their field. These people have claims that are better than IT for truly being "knowledge workers".

So the moral is this. Evaluate what you are doing and what your tasks are. Evaluate how you do or do not have to be available to interact with people. If you truly do not need to ask questions, be available for trouble-shooting, etc, then indeed individual productivity is the only thing that matters. But if you depend on other people or other people depend on you, there may be a real need (or sometimes just as importantly a perceived need) for you to be available at predictable times.

Note that available does not always mean present. It does not always mean that everyone has to be available. But that is the need that needs to be addressed, and unless you address it you will encounter quite a bit of resistance.

In addition remember that IT is unusual in that people can be productive on unorthodox schedules. This conflicts with what people from other departments will have seen, heard, and experienced in every other field. Be aware of this. Do not lose sight of this. After all if you do not know why the other person feels as they do, then you will not know how to address their concerns.

Finally note that this is not a criticism of attempting to make times flexible. The benefits that people have talked about exist and are very real. Rather I am pointing out why flexible schedules are a potential problem so that you can decide what and where you can give head off real concerns while maintaining flexible hours.