Never was he so relieved to see this kind of message! It was so obvious, but it might just work: Time-limited trials before giving a definitive 'go ahead' was the way to go.
Now, if only he could safely try this....
He figured the safest test he could do was to change one of his clothes: worst case scenario, he'd buy another one.
He grabbed an old, red t-shirt in one hand, while holding the stone in the other.
"I wish that for the next 10 seconds only this t-shirt would be blue instead of red"
The stone began to glow and got warm to the touch. When he looked back at his t-shirt, it was blue as expected. He counted to 10, never being so focused as he was now by the color of a basic t-shirt.
6...
5...
4...
3.... The anticipation was growing
2....
1.... Any moment now
0....
And then, as if nothing had happened, the t-shirt was now red as ever. Jon was relived: he actually had the safety switch he wanted.
Now on to phase three: would people really act as if wishes granted by the stone were the only reality they knew?
This was a bit more involved to try, as Jon would have to think of a wish with enough of an impact that he would expect people to react to the change.
What could he wish for now?
