Ideally we’d see something opt-in to decide exactly how much you have to give back, and how much you have to constrain your own downstream users. And in fact we do see that. We have copyleft licenses for tons of code and media released to the public (e.g. GPL, CC-BY-SA NC, etc). It lets you define how someone can use your stuff without talking to you, and lays out the parameters for exactly how/whether you have to give back.