If I had a nickel for every time I'd come across a dragon with illusory/mirage powers associated with the name "Shen," etc...
(Tsukimichi was the other one, this just prompted me to look it up and realize it was a mythology reference)
Yeah, five drones going missing when delivering to the same location is likely to get investigated unless the drones are super cheap. Like "comparable to the price of the packaging" cheap.
Why are you trying to "prove" it, though?
You might need to be tactful, and refine wording to assure her that she's safe telling you, but you can just ask her.
"Proof" is for "I need the authorities to come and take her into custody."
So....who got thrown? If I'm reading right, I'm guessing Yura, with the intention of getting her out of earshot of whatever type of "conversation" comes next?
My suspicion, at this point, is that the plot is going to lead towards "Dad has already moved to stop this rebellion, because the The Third Prince hasn't been as clever as he'd thought he was in setting this up." and that the MC will be allowed to stop this usurpation in public, when whoever...