Thats a very good possibility, but the big picture would dictate they would get all the information they can before doing a hiyaki and running.
I think they were logging aircraft, troop and ship movements from Okinawa, and had been there for some time. Counter-detection and detection was definitely part of the game, in my opinion.
Worst case scenario for them is to be depth charged to the surface and the surviving crew (if there is any) tried for espionage....but it wont happen.
Best case is they will be tracked back to port and a formal complain lodged against the Chinese govt.
Aren't there major American naval assets in Okinawa? Why weren't they detected by our antisub devices? Why did the japs pick up on this threat first? Or did we just toss them the ball for the followup? IOW, we detect the bogey and give it over to indigenous forces to check out? I'm foggy on my geography. How strategic is Okinawa? What would be the future use for data collected from such a recon?