Centreplate up or down when leaving the boat?

Do you leave your centreplate up or down when leaving your boat on a mooring or in a marina? Having just lifted Scout out of the fertile waters of Poole Harbour it was clear why the centreplate was getting stiffer - it was absolutely covered in weed and barnacles as of course it wasn't anti fouled. The rest of the hull was not too bad. The biggest problem however was when I tried to raise the board to put her on the trailer as the inside of the centreboard case was fouled up with barnacles and the plate would hardly go in all the way even after being pressure washed clean.
I've been leaving the plate down thinking that it made the boat more stable in the event of a gale or big wash, but it has left me with a bit of a problem. If I left her with the plate up will the fouling still happen and wedge the plate in?
All views gratefully received!
I've been leaving the plate down thinking that it made the boat more stable in the event of a gale or big wash, but it has left me with a bit of a problem. If I left her with the plate up will the fouling still happen and wedge the plate in?
All views gratefully received!