I was hoping you would use this solution in your extension and make it an official update. I don't attach a file as the solution is very easy to implement and checking both files either by human or machine takes longer then applying the solution ;-) so please just check the link.
thanks for your post, however your solution is not realy correct. In older versions of PHP it was allowed to name constructor same as the name of the class, and this is the case. So actually, plgSystemN3tComingSoon is not function, but constructor. So the corect solution would be to change
function plgSystemN3tComingSoon(& $subject, $config) to public function __construct(&$subject, $config)
However as there is no big deal in the constructor, it could be even completely removed.
This will be covered in future n3t Coming Soon release.