Similarly, if you are behind a structure or barricade that is not rendered for another player, they might appear to 'lock on' to you through walls when really they just can't see the structure.You can see players through unrendered structures and barricades if they are far away enough or your View Distance is low enough, and it might look like they are floating/flying.You can shoot players' limbs if they are sticking out through solid walls or floors, such as when they are prone inside guardtowers (this is the easiest trick in the book, and is the number one source of admin complaints about hacking).
However, a lot of players are mistaken/mislead when they accuse someone of hacking, so make sure you remember the following: If their profile is new and private, semi-red flag (perhaps they have not received any VAC bans yet?) If their profile is new and unturned is their only game, even more suspicious If their profile is new (not more than a couple months old), a bit suspicious (This is such a red flag that admins and server owners should ban any players with such a recent VAC ban upon noticing them, even before anyone accuses them) If their most recent VAC ban occurred over the past month or few months, huge red flag. If their profile says they have multiple VAC bans, even bigger red flag. If they have any VAC bans on record, big red flag. You should be able to use their profile as sufficient proof when talking to an admin, provided the admin is rational (which unfortunately isn't very realistic) If they can't turn around and shoot a different away on demand, or seem to 'lock on' all their shots onto where your head should be you when you are safely behind a structure/ barricade, or if they shoot and kill you when you're in a completely enclosed space, those are also all red flags. If someone clearly isn't aiming at you or even looking in your direction with you when they shoot at you, that's a big red flag. So firstly, assess how they play and see if it's suspicious.