I've got a video I uploaded on YouTube right now with that same warning. The video still plays fine -- the very next heading under the screen-shot part he shows says "What should I do?" in bold, and beneath that "No action is required on your part. Your video is still available worldwide. In some cases ads may appear next to your video."
The only difference I notice in the video is that an ad comes up showing people where they can purchase the song I used from Amazon.