I dont know that some folks dont get aggressive. I did read a few years ago of a person's abduction testimony where he had been abducted as a child, and in the ship was also a young guy and girl picked up probably during a necking session in thier car.
The young guy was very volitile and kept swinging and lunging at the grey's who had him strapped down--and one alien used something on him to make him paralyze rather quickly.
So who knows--and how many incidents never go reported, because the person's know they will be considered a psycho if they share thier story!