You should probably be aware that this is a competition between you and the other students, and whether they are lying or not about studying, you are up against them. This also regards their future. Don't ever let your guard down feeling confident just because people say they aren't coping so well etc. Because I know, even when I say that, I will do anything I can, finding the best resources etc. to maximise my scores.
As with notes, I don't think that many people will be willing to share theirs (their own sweat and tears), yet if they do, I don't believe they'd be purposely providing you with incorrect info. Make your own notes, make sure you've covered all your content and use a lot of sources while you're at it (good for practise questions). Don't rely on other people to help you.
Not matter if they are your closest friends, when it comes to school, it becomes a different story.
That of course, is just my own experience.
Hope you're well.
