Why not just even openly post it and make a note on their website that it is only for non-EU customers and also mention the reason and put a link to the exact law. Would that get them off the hook?
On the other hand when you are filming something do you really have a scene in a film that is longer than 30 minutes? Realistically your scenes are much shorter so the utility of having a camera that could shoot longer is probably low.
Say a concert? (I don't know anything about cameras, I was just thinking about that same thing and realised there are probably some uses for scenes longer than 30 minutes.)
For instance, one way in which that could be struck down is to use that message as a pretext to levy the fee anyway on this camera.