That happened way before, the whitepaper defines the purpose of downvotes. The delegators also talk to each other, checking opinions, but they all are going after self rewarding behaviour only.
Trailing is a part of steem. The trail was created before I registered the account on steemauto, I just added a description and declared it official after I was notified about that. The only difference between a delegator and a (dv-)trailer I see is that the delegators make the decision what gets chosen, and the trailer can easily decide to stop following if he doesn't agree with what they choose. Oh, and of course people on the trail open themselves up for retaliation, but I tried to make sure to make them aware. It also usually stops when they unfollow.
Or maybe you mean the feeling someone who gets hit by a trail gets, as seen here? That's not up to me though. I had plans for an upvote trail, but never one for downvotes. And even that only after I was asked about one several times.
I somehow also doubt he would've reacted differently with a single downvote. Maybe a bit less rage, but probably a lot more retaliation for the individual.
Or was that about the upvote trail? That allows us to give even more votes without getting near dust value, so I appreciate it. It also allows users to vote manually when they have time for it, something delegators give up on. So it's two different ways for two different types of people.