Would only add that if they do return, then those who are concerned about waking any children could easily disable the sound... or keep the volume low until you want to play music or video.
In the past (not on MN) I've had annoying noisy ads at 3 in the morning. Firefox has has an add-on called FlashBlock or similar which changes any embedded Flash so it does not "play" (but you can play it by clicking it if you want, and it shows a triangular 'play' symbol).