Yeah flames might not be very discreet especially if you are trying to stealth camp. Grey man is probably the smart choice.
With flames Everyone would either be like that's awesome and be jealous of your life with girls ligned up at the door or the van would get impounded lol.
Thats fine if he's wearing leather pants and a Motley Crue Tshirt, sitting inside his sweet custom painted van, doing blow and sipping Gentleman Jack. But what if Viking is the more studious, down to earth rubbertramp who is calmly perusing Voltaire's Candide, in slippers and a scarlet houserobe, when all of a sudden groupies show up and start raisin a fuss outside when he mumbles at them to "return at a decent hour"??!!