Good point. I investigated those single button pendant things for the DW, and found that in general, they are expensive, and simply end up with them calling 911. Also, it was a dedicated single purpose item, something I tend to try to avoid.

We decided that the DW would simply keep her cell phone on her or within reach at all times, and then, as has happened, she can call for help as needed (e.g., me, neighbor, 911, etc) depending on the need. Gives DW more options, and, she still can use it as a phone!