We'll respond shortly.
Essentially the gist is "if you don't have a URI, then don't use the anchor tag". That means not using markup like
I did the first pass of a refactor and started to use a span element before Berger pointed out that that was probably just as non-semantic as the anchor element. I had to concede the point.
For our case, the best option was an input element with type button. That summed up the best interaction for our use case; manipulating the DOM on a user action, without referencing another resource or an anchored point within the current document.
The thing is, it's a small change and there are so many examples on the web where the href=# pattern is used. It does work, so why bother changing it? Well yes, while it might work, this isn't the purpose of an anchor tag. There are other elements that will work just as well for you and make semantic sense. If we do that, then we can all make Dan a little happier.