Sure, but licences are not free to obligate anything at all. A lincense cannot legally obligate otherwise illegal behaviour, for example. It just wouldn't hold

Sure, but licences are not free to obligate anything at all. A lincense cannot legally obligate otherwise illegal behaviour, for example. It just wouldn't hold up in court. My question is about how far licenses can circumscribe non-illegal behaviour. There are clear pathological cases that probably wouldn't hold up in court either. What if a software contract says that you must turn over your first born child? I image that the software company would have to provide some very good reasons for including such a clause. So, how far can a license actually go?