Oh, I see what you're saying now. The *combined* weight of everything being more than 2x the weight. The way you worded it made it seem like you were talking about the trailer itself being more than 2x the truck.
At the end of the day, it's a figure of speech. If you're hungry, could you really eat a 900lb horse?No. If you were mad at someone, is a sane, reasonable, logical person really going to kill the other person? No. Does anyone really not notice a big camper behind them or that notice being 0%? No, of course not.