Yes, this is what a rational person would do. However, as far as I am concerned, "block," would likely be used to keep irrational people out of my Hubski experience. As of yet, I cannot think of an instance when I would have used "block" on an actual user of Hubski, but I would for some of the comment spammers.
If I were to see that another Hubski user was blocking people frivolously, I would think less of that Hubskier. I might even "filter" or "mute" that user.