Actually, it wasn't unreasonable. If the guy caused the damage while picking up a sonde, to know who's sonde it was would help identify the culprit.
Or maybe the sonde continued transmitting and they have data on where the guy took it which would help ID him.
Fair, I guess, I just can’t imagine what it’s like getting all these weird requests and demands for a hobby project. Hopefully the author is more entertained than I would be.