I understand the cost and technical constraints but wouldn't an exposed interface allow repeated calls from different endpoints and increased knowledge from the attacker based on responses? Isn't this like attacking an API without a response payload?
Do you plan on sharing a simulator where you have 2 local servers or similar and are allowed to really mimic a persistent attacker? Wouldn't that be somewhat more realistic as a lab experiment?
I love the idea of showing how easy prompt injection or data exfiltration could be in a safe environment for the user and will definitely keep an eye out on any good "game" demonstration.
Reminds me of the old hack this site but live.
I'll keep an eye out for the aftermath.