Being as I drive mine almost daily, if it's a light rain or I think can make it there and back without getting "to wet", I go. Every once in awhile I get caught in a bad down pour. So I drilled some holes behind the seats so the water can run out.
Different strokes...
EDIT: On occasion I actually LIKE to take the ERA out after a light rain or a wet road. It's real easy to get it "side ways" with light throttle and with a little experience can be a lot of fun at low speeds. Like driving on a dirt or snowy road and playing with the car.