While testing this I had to save the record before hand, then click the button, the page would reload and the checkbox would change and the action would fire. This is okay. If I pressed the button before saving it would ask me if I would like to save any changes, and even when I said yes I would lose them, though this just may be on my end.
Maybe the next best thing is to incorporate the checbox flip into a button that saves the record. Have it flip the checkbox then save the record. That way I could hide checkbox and give them a separate option that if you click here to save it will create the activity for you
