Skywarn is not ARES, nor does Skywarn depend on ARES - or even ham radio - to operate.
Apples and Oranges.
I would agree that they are different, and that SkyWarn is not exclusively amateur radio. However, in the part of the country I live in it is amateur radio that handles all the SkyWarn traffic. If this statment was made in response to my SkyWarn comment the issue I was trying to bring to light is what would be classified an emergency by each individual agency. I agree that ARES and SkyWarn are different. One of the key points of this whole discussion, however, was that emergency management/public safety/government groups would be the ones who might need to pass sensitive information via amateur radio (a very unlikely event in my opinion and experience) in which case they, not the amateur radio community, would be the one to determine which emergencies required encryption and which did not. So, my point was, if this decision was left up to the EOC or EM staff, what might they decide was or was not an emergency or what was or was not "sensitive". I still see it as highly unlikely that in most, if not all, situations amateur radios would be used to pass sensitive information. Simply put it is a huge liability issue, and a major risk of leakage, because you are asking a volunteer to be responsible for sensitive information to begin with. One could argue that in the event of a major emergency at a hospital that the volunteers who normally give directions, etc. might be used in other areas, but I seriously doubt, regardless of their level of training, that they would be used in any direct patient contact or high liability areas. The same is true in this case I believe. If amateur radios were needed to replace any EM, EOC, or public safety communications on this scale I would assume that they would be used to pass the non-sensitive information. As others have pointed out, if the situation became such that all public safety repeaters were inoperable then it is a good chance that amateur radio repeaters would probably also be inoperable. In that case for longer distance ops we might be looking at HF communications, or a relay type system where operators are placed at strategic locations to forward comms around the area. In both of these cases the situation would have gotten so bad that one has to wonder how many volunteers, amateur radio or otherwise, would be willing to, or even could, come out. Passing information such as the location of fatalities in an encrypted mode is really uncalled for. If the situation is such that any repeaters still work the chance is that cell phone towers also still work, so the public, media, etc. will find this out through other means. As a more recent example, I would assume that more people, even those in Boston, heard first about the marathon bombing via cell phones, social media, etc. than did by monitoring Boston radio comms. That is just the facts of the age. Almost everyone carries around their own "radio" known as a cell phone.
Christian KF4ZMB