so I finally went and tested this..
first - build something that you have to crouch to get under.
crouch and go under -- make sure it works
try to go under w/o crouching -- make sure it DOESNT work
then goto the console and enter:
playerstandardarmor.crouchBou ndingBox="5 5 10.6";
now crouch and try to go under your bricks.
It wont work.
So to "fix" this, go into your mod, and inside the command that starts things off add this:
playerstandardarmor.crouchBou ndingBox="5 5 10.6";
Now it will LOOK like the player crouches.. but, it will have no effect.. they will still get hit by stuff, and they wont be able to crawl under things.