Well, I suppose some more debate is in order here... Just as some actresses are less bashful in front of the camera than others (we're all thankful for the Anne Hathaways and the Monica Belluccis of this world, but as I've said before it's a crying shame that we live in a time where Kathy Bates has appeared on film naked twice while Jessica Alba and Scarlett Johansson haven't. Yet), some models have been more happy to share what they have than others - Alessandra Ambrosio, for instance, has not posed properly nude AFAIK, whereas Diora Baird has willingly taken one for the team. Similarly, in the higher echelons of supermodeldom you've got people like Lauren Hutton still posing nude at 60 and Naomi Campbell stripping on request, and at the other extreme Claudia Schiffer not quite approaching Aishwarya "is she really going to be on Heroes?" Rai levels of chasteness, but definitely in the ballpark - you can certainly imagine her suing again if anyone ever gets her topless.
Although I'd still adore Cindy if she fell into the latter camp, it doesn't hurt that she's in the former... both print magazines (Vanity Fair, GQ) and film (Fair Game and The Simian Line) have benefitted from Cindy's charismatic corpus, but her most famous spreads were undoubtedly her layouts for Playboy. She posed in 1988 in a successful bid to increase her reach to guys (making Cindy one of the very few women to strip for the Rabbit in an attempt to boost her [admittedly already healthy at that time, though in smaller circles] career and actually boost her career) and again ten years later when she was 32; with that time coming around again, Cindy's made it clear more than once that while it would be good for her ego (and for Playboy, whose celebrity pictorials haven't been that heavy on the celebrity count lately - ex-contestants from The Apprentice? What is this, Nuts? - she won't be taking it all off for Hefner again, for two reasons:
1. Between 1998 and 2008, Cindy became a mother to two growing children and she doesn't feel that her kids (especially, presumably, Presley) need to get any hassle from people on seeing their mother naked in one of the world's most famous magazines, getting teased about having such a hot mom etc. (The fact that Kaia had her own mini-controversy modelling swimwear for Melissa Odabash can't have helped.)
And as for point number one, they say that children give you new priorities. But this also brings up the question of her previous layouts - Cindy's not a stupid person, and she surely knows that the possibility of people "researching" her other work for Presley cannot be ruled out (not to mention the press reports of her lapdance in St. Tropez, etc.) And that's assuming he doesn't already know... and if you're being rude to paparazzi at a young age, like he's been known to be, then he probably does. On the other hand, it's highly unlikely that Pres is going to go up to Cindy and say "Mom, I don't mind you posing naked" - how many boys say stuff like that to their mothers? Better not add any more fuel to that fire.
So I'll just say that I'm happy for Cindy to continue to do magazine layouts of the tastefully hot variety. But I'll also say that if she is persuaded to change her mind and strip off at 42, there will be no complaints from this corner. Or from the corners of a lot of men who were teens in the 1980s. Or the 1990s. Or, in some cases, the 2000s.