Yep, then they turn around and file a class action law suit against Blizzard.
There is no legal ground in this case.
It’s like stealing from a robber and going to the police about it.
Blizzard does not care, if anything Blizzard will not do anything at all, just to get their hands on that source code.
Their threat doesn’t carry any weight unless they go through with it.
And in this case I hope they do.