Over two years ago, Google started showing a message in the snippet for those who blocked GoogleBot from crawling their site, to explain to the searcher why the description is not showing up.
Now, Google is showing this message to mobile sites that are blocking Google as well.
Above is a real example I spotted on my first try searching for [deals]. I should note, the site does show the description on the desktop version but not the mobile version. Why?
Google's Zineb Ait Bahajji said on Google+ that they have brought this notification to the mobile results. She said that Google will "display a message in place of the description snippet for mobile search results blocking Googlebot for smartphones, just as we already do for search results blocking Googlebot." If you block "critical resources such as JavaScript, CSS or images files," you may see this message in the snippets.
Here is a picture of the same site showing the description on desktop:
Google really, really, really doesn't want you to block them.
The learn more link goes here.
Forum discussion at Google+.
