Restarting all the authorities at once would halt all the clients.
For a while after an authority has started, it doesn't have any opinion about which routers are Running, so it doesn't vote on that. But if every authority were restarted at once right before it was time to vote, no authority would vote on the Running flag, and so no router would be listed as Running in the next consensus. Clients would then think that all the routers were down.
Let's fix this DOS before it happens. One possible fix would be for authorities to refuse to build a consensus if nobody has voted on certain essential flags, to include running. As a belt-and-suspenders approach, newer clients could assume every router was Running if nobody voted on Running, rather than assuming no router was Running.
[Automatically added by flyspray2trac: Operating System: All]