MsMarmitelover runs an underground restaurant that had plans for a couple of Harry Potter themed nights. Small scale stuff really and no threat to a major brand. Until that is, somewhat ironically, a big brand waded in to assert their rights.
The result, somewhat predictably, is that this operation has had more publicity than it could have dreamed of and even I am now thinking of setting something similar up in my local area.
What has the brand gained? Er, nothing really. What has MsMarmitelover gained? Loads!
The brand needed to assert its right to prevent the problem getting bigger of course. Or did it?
Imagine if the brand did nothing and just watched stealthily what happened next. A tacit 'product development' focus group would result leaving the brand still able to assert its rights down the line and giving them valuable insight they might not have thought of.
By showing their hand too early they squashed the idea and will now never really know the value of the idea. Meanwhile MsMarmitelover gets to enjoy loads of free PR and develop a competitor.
That means, assuming brands do this lots (and they do) and that good ideas occasionally result (and they do), that somewhere they have just willingly dumped revenue.