Scones ARE more forgiving, as their ingredient mix is less sweet and the baked moisture content is lower. Muffins and cakes undergo a chemical change that creates the sticky tops (basically sugar, as well as being a sweetener, causes a softer crumb in baked products. It helps with the shelf life because it absorbs moisture -- but sugar attracts airborne moisture, making a sticky top). This can be disguised a bit if they are topped with streusel or the like. Otherwise, freezing is best for storage.