I never heard of this. Only time I ever used Silicone spray was when I had to stuff cushions. Trying to wiggle a foam cushion wrapped with dacron into a a sewn cushion cover is like wrestling a big dog into the bathtub....LOL
I started to wrap the cushion in a large plastic bag and sucking the air out with a shop vac and then putting it into a cover then shutting off the vacuum and working fast enough to get the corner set just right before it fully expands again.