I would like to know the same thing. The BYOD devices would need to be supervised.

No, Casper Focus requires that devices be supervised by Apple Configurator, which I assume would never be used with BYOD.

Is there any way Casper Focus would ever be available to unsupervised devices? We are not supervising our student's iPads.

I just went to a CMA training and learned that the Supervision requirement is something that Apple requires to use features like App Lock. Until Apple loosens that requirement (which is not likely) I believe you will have to have all devices locked.
I am helping run an iPad program 1:1 with 800 iPads, blended with BYOD and school owned (leased to the parents) iPads. We are making supervision a requirement. Even the 200 that we did in a pilot this school year, we will be requiring all iPads to be erased and placed into supervision mode to be a part of the program. This also will allow us to force a restrictions profile and other settings onto the iPads to help maintain a consistent environment.
Lastly, a little beyond the scope of the question, but Supervision is great not only for the Casper Focus, but you can force a proxy which can provide content filtering on and off campus.