He cites Harold McGee, who tested this theory in his book The Curious Cook: McGee weighed 252g fresh mushrooms, submerged them in water for five minutes, then removed them, blotted the surface moisture and reweighed them. The result was 258g, which, as McGee noted, is a 16th of a teaspoon of extra water per mushroom. This was after five minutes of soaking, so five to 10 seconds of rinsing under running water is going to make no difference whatsoever.
The joy of eating strawberries extends beyond their sweet and tart taste; one of their best qualities is just how effortlessly snackable they are. All you need to do is give one a simple wash and pluck out its stem before munching on it. As it turns out, however, there is merit to giving strawberries some extra prep. It may seem unnecessary to peel a strawberry, but there's a reason why you should - it improves the flavor and texture of the fruit.