An interesting idea.

I am not sure what the best approach is. Certainly I believe that multiple time vaults will be required at some point. How to be proceed is up to people above my pay grade. LOL

It is something that will have to be worked out. Having a sliding scale that the witnesses can alter is an interesting idea. They could change both the interest along with the time.

That would allow one vault set up. I wonder, once in place, how hard it is to add more. Can that be coded in and put live if the witnesses determine?

These are questions that the core devs might have to opine about.