Yesterday, we reported how we saw emojis back in the Google results and as a coincidence, someone asked John Mueller in the Google Hangout on Google+ yesterday if Google will penalize sites that do that. John Mueller said no, they will not.
At the 35:55 mark into the video, John Mueller answered this question:
He said:
So if sites are abusing it, Google will try to strip the emojis or symbols out of the display in the snippets but not remove the site or demote the site in the Google search results.
Here is the video embed:
Forum discussion at Google+.