How easy is it to game the altmetric score?
Like any metric, there’s a potential for gaming of altmetrics: 
  Anyone with enough time on their hands can artificially inflate the 
  altmetrics for their research. That’s why altmetrics providers like 
  Altmetric, PLOS and SSRN have measures in place to identify and correct for 
  gaming. Don’t forget to look at the underlying qualitative data to see who 
  has been talking about the research, and what they’ve been saying.


I conclude it is very easy to game the score.  Gaming is also easy to detect.  Gaming altmetrics is neither ethical nor useful.

https://www.altmetric.com/about-altmetrics/what-are-altmetrics/