Interesting. I phoned and complained about this as soon as Netflix started doing it - I think it was about two years ago! What really got me (and I pointed this out to the cutomer service rep) was that the first preview that showed included several swear words. I thought that that argument alone would be enough, let alone how annoying it is to have a stupid light and sound show while I am browsing.

So all I can say is "about time"!