Here is a true story which took place and witnessed with my own eyes.
Many years ago I was on shift in a small off strip Las Vegas casino.
I get a radio call to bring a single keno ball #46 to the keno game manager on shift working in the keno lounge.
This person was a 60 ish 15 + year employee . I asked her the reason for the #46 ball ? , since this was a first for me in all the time I was employed their.
Her reply was "Don't you hear it" , Hmm hear what as the keno balls where mixing in mid air inside the plastic bubble. She said the #46 "SOUNDS" like it has a crack in it. I do not hear anything different at all. OK game over.
I now have to open the top of the machine to retrieve the #46 ball, well what do you know, sure enough and with very little finger pressure the ball splits in two as soon as I picked it up. Why it did not split apart while colliding with the other balls is amazing.
Anyway, the point here is you can not even trust the air ball machines , however I still prefer them over a computerized draw.