Can a Riva 510 be used SAFELY without the cone that screws around the atomizer? I got the Riva 510 lite bundle which, as we know, comes with two complete Rivas, minus one cone. My brother want to buy one and wants to know if it can be used without ordering a cone. Told him just to buy one.. They're like, $5 or less, but he's lazy like that. 
