Are papers on Research Gate publicly available?
In my experience, the papers are often not online, but RG let's you "request" a paper, meaning the website sends a canned email to the author, which they may or may not respond to. This is regardless of whether or not the user has an account. RG infamously listed authors with their publications who never registered, and these would thus receive all sorts of spam. I'm not sure if that is still the case.