i've played hardcore because of contracts and this is literally all i see(I'm not bashing hc players in any shape or form, it's from my perspective). I usually see them being very defensively, as in walking with the scope on, prepared to shoot quickly. I've almost never seen anyone use Motion sensors although i've used it many times and been successful. What's also popular from what i've seen is that they hide behind visual cover. Whether that is laying prone in grass, posting up in unusual places(compared to regular core). But for hardcore FFA, this is what i would do. Hide in an area until you see that someone has been killed, they are likely to spectate you so move around a bit and then when they respawn, return to your position. if you killed them multiple times, switch up the location, they will know where you are hiding.