By Daniel Kline The cruise line has made a move that Carnival will struggle to match. Royal Caribbean (RCL) – Get Royal Caribbean Group Report and Carnival (CCL) – Get Carnival Corporation Report endlessly try to outdo each other. The ships get bigger and the activities get bolder. One line adds virtual reality, so the other puts a roller coaster on its newest ships. This battle has benefitted passengers. Cruising used to be about the stops, spending time on the pool decks, shows, and eating in the main dining room. Now, you can — at least on certain ships — play laser tag, then ride the bumpe…