It seems to me that DOD's under trunks would be much easier to manage if they were put under extension settings. I can't think of a single case where I needed to associate a DOD with a trunk, it's always an extension.
The issue for us is this: All of our extensions are hosted, and are a variety of different companies and users. Our provider determines the 911 address based on the incoming caller ID, which is set for each extension.
Since the setting of DOD's is under trunks, and not the extension, it can be very easy to forget to set it. If this isn't set to an associated address with the provider, their fee is $350 for a rogue 911.
Further, this number has to be entered under each trunk. If you have a primary, secondary, and more, this gets to be a real pain quick.