Cheaters are getting more and more numerous all the time; they have to take steps to not be completely overrun.
My wife got eliminated by a 100% invisible player a week or so ago. No in-game item or event makes you completely invisible like that. The stealth splash item and the hide-and-seek event are both imperfect camoflage. So clearly this player was hacking. If she encountered players like that in every game, she'd quit, understandably.