Coyle: Hey, Baxley! If your mom's vagina were a video game, it'd be rated E for everyone.
Traeger: Do you know what my job description is? I'm in acquisitions. I look up and I catch what falls out of the sky.
Casey Bracket: Do you have a plan? Ex-sniper with ptsd and a team that's mental? You're insane, right?
Coyle: Yeah.
Traeger: Predators don't just sit around making hats out of rib cages. They conquered space.
Quinn McKenna: Look, I get it. Something went down in Mexico. Nobody wants any witnesses.
VA Psych: I need to know if you pose a threat.
Quinn McKenna: I'm a sniper. Isn't posing a threat kind of the fucking point?
Casey Bracket: I think they're attempting hybridization. They're upgrading on every planet they visit.
Casey Bracket: What's on the ship?
Traeger: I think you know what's on the ship. The ultimate predator.
Answer: Well, in the case of Predators, it was violent criminals, mercenaries and military being randomly kidnapped and dumped on an alien planet. From the perspective of humans, it would appear that the criminals and mercenaries had gone missing in a more mundane fashion or simply died. If the Predators were covert about it, the Predator researchers would not be suspicious at all. So it's entirely possible it's canon.