Actually I found that quote when I was searching for some of the FEA stuff jluetjen did. I also did some models which were on a laptop that was stolen, and haven't taken the time to rebuild them.
Its show that if you removed the knee bar the stresses in the cage remained the same, or in other words,the cage performed the same with or without the knee bar
If you get that bar tucked way out of the way fine, you carry around a few extra pounds.
I think one overlooked spot in cage construction is the floor. I've seen a car that was balled up and the pedal cluster was pushed almost halfway to the seat
I saw pictures somewhere of a car with some floor bars, Gunnars sight maybe?