This is so prevalent that there are many study groups on facebook just because of that: it is the only place they can "freely" exchange ideas, and voluntaries from other countries (without these limitations) help by copying and pasting info and documents so others can 'freely' download it.
https://www.theguardian.com/world/2016/aug/01/facebook-free-...
https://www.theguardian.com/technology/2017/jul/27/facebook-...