Here is a hand from Batman-Superman match where i feel guilty of using UI.
Against 3 NT I led ♥J which was held by K by my pd Csaba. Then pd played ♥8, declarer 9 and I won with T. I was trying to figure what to do. 8 looked like from originally K8x. Which indicates that declarer had Q9xx. This also means declarer has 5♠+4♥ and only 4 cards minors. So I thought even if ♥ A blows a trick, declarer still needs diamonds and as long as he does not have Q or has stiff Q I would be fine. Also I had an UI that for some reason I did not see it as such during the game. It took forever for Csaba to play ♥ after he took ♥K. Why would he think so long if he had only K8x. Having left with 8x it is obvious even for a beginner to play the 8 right away. So i knew he had hard time to choose whether to play the correct card of smallest from 8xx or try to make a forcing play with 8. Csaba should have played smallest because if declarer has 4 hearts, which makes me lead J from AJTx or AJT9, 8 does not have the force ability in any case.
So I cashed the A dropping the Q. Thank god it did not matter what I played, declarer was going down 2 regardless. But today when I watched the you tube version of the match, I realized that the information I gathered, which did not occur to me at the table as one, actually was an UI. I don't know why I did not see it as such at the table, perhaps because playing almost no live bridge for a long time and haven't been called TD on me.
I truly apologize to opponents even if it did not matter. It really did not occur to me at the moment that this was not an information I could use.