I suppose that's one way of looking at it. I just think of it as an ugly logo that doesn't do flickr any good. But then again, if you use the BBCode, you have the flickr text below the image and that too could be interpreted as advertisement, just as clicking on the image will take you to flickr. We have no way of doing anything about that. It's flickr. The only way to stop it, is to not allow images hosted at flickr and that is obviously not an option.
What you can do is remove the visible bits from the BBCode so the image is hotlinked. That way you have no flickr text and when you click on the image, it zooms in, instead of taking you to flickr. But that's up to people and not something we can enforce.