It does not blindly accept: the server does a lengthy verification to prevent cheating. This is more the area of the anti cheat team so I can’t really give too many details. High level, its checking things like rate of fire, max number of targets, distance and angle to hit target, etc. It does do a trace but its more for ruling out impossible shots / penetrating buildings (“yes you could have hit that”) rather than authoritatively deciding what was hit (“based on my view of the world, this is what you hit”).
Hope that clarifies.