Basically, I see nothing wrong with this. It's a pre-order bonus. AFAIK, you're not forced to use it. And it could be a programmer messing with stuff in the 'game'. Also, they do a lot of changing history in these games, right? By that, I mean there are things they say happened that basically didn't. Maybe the history that like is the one that had unicorns or whatever. In the end, if you don't want the unicorn, then don't ride it. It's just a fun little thing that others seem to be ok with.
My sarcastic post earlier shows why the unicorn is dumb.