[a_cardboard_box]

Unity is saying they can send developers a bill for whatever they want, and if it's not paid their game can't be installed.

Unity has published what "whatever they want" currently is. It doesn't matter if people get the details wrong on that because Unity can change its mind.

That being said, you're still more wrong than the author on the details. The change is retroactive in that it applies to existing applications. The author was very clear what they meant by "retroactive":

> this change will be done retroactively on existing applications as well.

This is true.