Companies have a legal department to make sure this kind of thing is followed, otherwise they have potentially huge liabilities. For things that have a single

Companies have a legal department to make sure this kind of thing is followed, otherwise they have potentially huge liabilities. For things that have a single author, the relicense option is possible, yes. But how about projects that have several? To me the great thing about software is that other people can use the code I wrote without it costing me anything. I understand the various attitudes of wanting others to be bound by some terms of sharing the work they do too, or paying for a license, but at least from my experience it limits the adoption of my code, and I'd rather my code be useful in as many places as possible, with the only requirement being that if you fix any bugs or extend the functionality in a deeply intrusive way, you contribute that back.