How do I unsubscribe from MCP?

I'd like to unsubscribe from one of Microsoft's MCP email feeds, but when I click on "unsubscribe", I'm presented with this this.

My first guess is that I just click "Submit" with the checkbox checked, but that's not how most subscription preferences UIs work, and some of my coworkers also disagree. To unsubscribe, do I leave the box checked, or do I un-check the box?

Really, something as simple as removing yourself from a feed should be something you can do BEFORE your moing coffee...