Here's a question. Right after you 'predict' the spectator's time, can you then lay the watch on a table, and let the spectator pick the watch up seeing if it matches their time? In other words, can you not touch the watch once you make your prediction?
Here's a scenario:
Your watch is set to 11.32. You set your watch hands to a predicted time. You then hold the watch by it's strap, to demonstrate you are not playing with the dial to alter the time. A spectator tells you their predicted time (eg 2.41). You say "ok, so out of all the possible hours and minutes in the day, and all the possible combinations, you chose 2.41. There was no way that I could have known this in advance and as you can see, I'm not even touching this dial to change the time now." Youthen turn the watch around to face the spectator, and it displays their time, absolutely perfectly accurate to the minute
You can lay it on the table if you wish, although to let the watch be in the hands of a spectator for any length of time is risky in my opinion.