It is a reality and I'm sure Genevieve and her people took all that in to account, particularly for last year's calendar given the nudity. If you are going to create something of interest a small percentage of people are going to share it so they can get the virtual pat on the back and the 'thanks bro' comments on a fan forum. But it's perfectly natural for her to hope that fans will have her artistic and financial interests at heart even before she has to put out her polite request not to share the images. Maybe she should put a similar request in with any future calendar project.
Last year my second favourite songstress requested (in advance of tickets going on sale) that nobody use phones/cameras in her concerts during a small tour of church venues....and as if by magic, to this day not a single clip of any of those concerts appeared on video sites except for professionally shot ones she released herself (for free!) and I saw no phones being used in the concert I went to.