Does associating an IP with a post constitute a punishment?

It does, in my opinion. It is an intrusion into privacy that could potentially lead to problems, but which would appear to serve no useful purpose. The problems, in other words, seem to outweigh the possible benefits. One issue is simply that for many people, their IP number changes from day to day.

I don't know if there are situations where a user cannot sign in. I do know that quite a few reasonable, respectful, and well-thought comments come from AM, for whatever reason. Maybe they're at work and keystrokes are logged, and they want to avoid giving away their password - I don't know. But some people do post good things anonymously. Still, I am not adamant about all this. I think the community will form a consensus, and that's how we'll go. I might not agree with it, but I'll abide by it...