I think the first question that should be asked is whether work is getting done appropriately. Are people meeting their deadlines? Is their work product of good quality? If the answer is no, then you have to address it, establish performance expectations, and hold people to them. If the answers are yes, then yelling at people, acting like a bully and stealing from them (and that is what it is when they aren't paid for their time) is the worst possible way to manage a business. THE WORST. This is especially true with jobs that require creative thought like the ones you mentioned. The danger from the company's perspective is that when you treat people poorly, you are going to build resentment and it is going to come back and bite you when you need people to go beyond a minimum effort.

It's like the movie Office Space, when the Bobs are talking to Peter Gibbons, he tells them that, "...my only real motivation is not to be hassled, that and the fear of losing my job. But you know, Bob, that will only make someone work just hard enough not to get fired."