Thought on Blogger changing it's policy on adult content next month

So this notice popped up on my dash just now:

Starting March 23, 2015, you won't be able to publicly share images and video that are sexually explicit or show graphic nudity on Blogger.
Note: We’ll still allow nudity if the content offers a substantial public benefit, for example in artistic, educational, documentary, or scientific contexts.

Changes you’ll see to your existing blogs

If your existing blog doesn’t have any sexually explicit or graphic nude images or video on it, you won’t notice any changes.
If your existing blog does have sexually explicit or graphic nude images or video, your blog will be made private after March 23, 2015. No content will be deleted, but private content can only be seen by the owner or admins of the blog and the people who the owner has shared the blog with.

 There's always Tumblr, which doesn't have such a restriction on adult content. What bothers me is what falls under "adult content". Obviously porn does, but what about just a nude picture? Are they going to drop the hammer on a blog if someone posts a picture of a pinup or something and there's a nipple showing? What about butts?

I'm also just curious how Google is planning to enforce this new policy considering how many blogs there are on Blogger.