From the perspective of trying to keep companies from doing this in the future, that's not really relevant. Trivago gets hurt just as much of the money ends up

From the perspective of trying to keep companies from doing this in the future, that's not really relevant. Trivago gets hurt just as much of the money ends up with the government or with the customers. Not that I'm against customers getting it, but if you look at it from a straight-forward "give incentives for companies to not follow Trivago's example" perspective, then fining them is enough to accomplish that.