I'm picturing them using themselves as the first sample set.
It appears that they can be beside one another, so long as contact isn't established. However, it could be useful to have such a mechanism work over distance as well. [People could even stay in their own beds rather than have to venture to a lab-like setting.]
Mm! I'm not used to having many people here who understand advanced programming. In my world it's fairly commonplace. [Battle sims and the like, mostly, but enough to base a prototype on.]