Slingshot has 4 white lines...lol... I ride both cabs and SS... On snow 5 months a year... Just stretch your lines, attach them, then roll your bar when not flying the kite.
When kiting in deep snow , you really dont feel like walking up and down to your kite. Also a lot easier to find wich way to twist the bar when launching the kite: in the winter I always use foils and i leave the lines on the kite.
Also ask yourself this simple question, if companies that make kites would offer the same model at the same price; one with all 4 coloured line and one with all four white line. Which would you honestly choose.