It's perfectly founded, because I have seen it happen. Back in the 80s was a Thatcher believer, still am really, but in the 90s I was a member of a moderate public sector union in the UK and saw it working from the inside. It was a real eye opener, the union had huge experience in health and safety (a significant issue in that organisation), the unintended side effects of various policies and procedures, all sorts of things and actually worked very well with management to represent legitimate concerns.

It doesn't always work, in some industries I can see the relationship is much more confrontational and damaging, but it doesn't have to be that way.