I worked for a couple of very "household name" big companies as a tech lead. I trained probably dozens of H1Bs over the past 15 or so years. I've seen it all. I decided that I would help anyone who wanted to improve their skills regardless of their origin or employment status, and that's what I did. I got mistreated terrible at times, in particular by a Venezuelan woman, but generally speaking, I helped raise the bar for a lot of people who maybe otherwise would have been ignored because big companies don't care about training people at all. As I look back on what my career was, I think that all the informal mentoring I did was probably my biggest contribution. I just wish it had turned out better for everyone involved. I saw a lot of absolutely heartbreaking situations arise over the years. And now my situation is kind of heartbreaking as well. We were all in this together, but nobody spent a single second thinking about that.