or they coulda been told to write that so that we don't go guessing the color too early.
they weren't nearly this careful with kyujukkies with the unveiling of their colors.. 9ki we figured out with the cover of a Hello! Channel volume, and 10ki's colors were being used in HelloPro TIME way before their colors were officially announced (it took fans a little while to catch on though).
i guess it's possible they wanted to be more dramatic with Sakura's color, but if that's what they were doing they probably should have used different neutral colors (black, grey, beige) on different things in order to throw us off. right now it's looking like it very well could be white~ guess we'll see. ^-^