I'm not sure if this is true anymore. For what it is worth, the Atlanta Journal Constitution reported that the boy's death was caused by asphyxiation, but there were no neck bruises.
"District Attorney Scott Ballard said the boy had internal injuries to the throat area, but showed no bruises, indicating he may have been locked in the crook of his father's arm. Previous reports have said the boy had been smothered or strangled."
So, I'm thinking it is might not have been the crippler crossface. Instead, this sounds more like he had him locked in the Million Dollar Dream. Unless the kid is strong enough to side suplex benoit or if he started to do those rocking elbows to his midsection to get out of it, he was screwed. He wasn't Hulk Hogan so he couldn't do the puffing cheeks thing and apparently Mr. Fuji wasn't around at the time either. However, if this kid was really short, it is possible that Benoit would use something similar to the crippler crossface and use his elbows instead of his hands.
But we shouldn't really start judging wrestling on any criteria based on Chris Benoit. Keep in mind that his main finisher, before he did the cross face, was him falling off the top rope and having his head smash into his opponent. I remember seeing a few times where he just rocked his head doing this.