Quick story I just remembered in thinking about this thread: I was playing 9-ball in the end-of-season league tournament, and I had missed. The object ball landed frozen to a rail and before I sat down I said "it looks frozen." My opponent got up, looked, and quickly agreed.
But his teammate started complaining "why does it matter," "he's sharking you" and the like.

I told the teammate that it's possible that a ball wouldn't go to a rail and it's good practice to clarify beforehand. He said he knew the rule, but he thought it was so unlikely to be an issue that it was unnecessary for me to say anything about it, and I had done it just to throw him off. It was true that he had an easy hit on the ball, and it was very unlikely to lead to a foul.
My opponent hadn't said anything more about it, he just got up and shot, and made an obviously legal shot. After the game I talked to him and said "I hope you don't think I was trying to shark you with that frozen call" and he said "oh no not at all, my teammate is just an asshole."