Please, look at this pic:
http://railpictures.net/viewphoto.php?id=308028&nseq=1Notice, no vestibule at the front of the lead Amfleet II. That means, in a derailment, or other rapid-evac situation, 60 coach passengers are now trying to get out through one vestibule instead of 30 sleeper passengers. Would the same situation happen with the trailing coach and the locked end-door? Yes, but A. worst-case, there's a window, and B. once you're through the window/door, there's not a locked baggage car door further inhibiting you because I assume, the baggage car side-doors are locked.
I'm not saying go back and give the Diner no vestibules, I'm saying, flip the seats, stick the baggage in front of the Viewliners and prevent a potential disaster.
Also, if the horn noise is really an issue, then why do the Superliners run with the sleepers up front? They're even more exposed to the sound than the Viewliners which at least are inline with the Baggage and P42 (roughly) which provides some dampening.