Finally I've tested new CP-2 anti twist mounting plate, http://store.nodalninja.com/product_p/cp-2.htm and I'm confirming that it does its job.
I also discovered nice "bonus" feature.
In Olympus E-30 camera, there are 4 buttons below the rotating screen.
When camera is carried around with neck strap, if camera is on, those buttons are often accidentally pressed by own body.
But not any more. CP-2 plate also added nice "protection" against accidental pressing.
See attached image.