Big companies definitely care a lot more about these things than universities or "small-time researchers". I've been in long meetings with corporate lawyers at

Big companies definitely care a lot more about these things than universities or "small-time researchers". I've been in long meetings with corporate lawyers at multiple big companies, and they are a lot more careful than you imply (because they have more to lose). It's always a risk vs reward thing. Things like "copyright doesn't apply here at all. You can use whatever training data you want as long as your model is sufficiently transformative." are not certain until they have been tested in courts, and will be different for each case (it's a lot easier to argue that a simple classifier is transformative than a GAN that might reproduce one of its training inputs, for example). An additional complication is that if you're a company that's operating globally, you have to pay attention to a lot more laws. Where I work now we work a lot with synthetic training data, because dealing with "real" data is complicated.