I think your buddy joking-not-joking about it is slightly different than someone who has worked somewhere for 8 years straight claiming that is exactly what happened to him and two other co-workers. Keep in mind that they are killing their chances of being employed by any other union-shy workplace which is 'most of tech'. So there is significant downside to this. Also note that he refused to sign an NDA that would have prohibited him to talk about it and which would have put money in his pocket, so there is some evidence that this person - by his own claims - is rather principled.

And then there is that other article linked in this thread which provides a ton more circumstantial evidence.