Blogger content policy does allow Blogspot blogs to host images and videos that may contain adult content but the owner is then expected to allow only private access to his blog, or now display the warning for readers. But if the blog owner does not takes the required steps and keeps on adding (adult)content to site, with no such warning and a someone reports the blog as offensive/spam, that could lead to a problem to the blog.
In most cases, Google would give a warning to the blog owner as below:
Some readers of this blog have contacted Google because they believe this blog’s content is objectionable. In general, Google does not review nor do we endorse the content of this or any blog.Well, as said in most cases, as it totally depends on Google. It may directly delete the blog right away, as the blog owner have violated the TOS and guidelines of Blogger. Still this seems to be good for readers as well as blog owners of such adult blogs. For readers, it would be good as in future, chances are blog owners would comply with the guidelines and TOS of Google and thus there won't be such instances that could lead to an embarrassing situation, whereas for owners it would be good as their audience won't be limited, all they have to do is add the warning following the procedure below.
1. Go to the blog that contains adult content.
2. Go to Settings.
3. Go to Other option.
4. There you can see the option for adult content, all you have to do is make it Yes, by default it is set to No. By making it yes, you tell Google to add a page showing warning about adult content to every visitor of your blog.