I've lived in the central WA area for 55 years and have done quite a bit of boondocking in that area over the years. I'm going to make a guess that a lot of the 911 calls are in the Quincy and Ephrata areas as I have read of several crimes happening in those areas.
I have personally boondocked north of Soap Lake at Blue Lake, which is in the Sun Lakes area, and the Coulee City/Banks Lake area and never observed any problems in either place. I have also boondocked in the Grand Coulee Dam area and Lake Roosevelt with no issues either.
Not sure about Moses Lake as that area never appealed to me.