Actually it works the other way around, and is considered to be a problem by many security experts. If you don't have a Hidden OS partition, and the court requests the password, it's impossible for you to prove you DON'T have one. Just like it's impossible to prove you just forgot your password.
So you're better off making a hidden OS partition and not using it, just so you can access it.
So you're better off making a hidden OS partition and not using it, just so you can access it.