I was playing High Tide in like the 6th round of a legacy event a couple of years ago, and I basically made a nice little spread sheet whenever I started comboing off that kept track of number of active High Tides, mana in my mana pool, and spells cast this turn in case I decided to just Brain Freeze someone to death.
My opponent was playing Counter-Top and was a real douche, and we were about to go to time, which is fine by me since I'll get another couple of turns and on one of them I'll win. So, proceed to time, I'm about to win on my 2nd turn of extra turns and he all snidely says, "I bet you can't combo off without your little sheet," to which I say I most certainly can, but will only do so with a judge present in case of any disagreements. He gets all bitchy, "Oh now you're calling me a cheater, huh?" which I was waiting for- I knew this fucker, and he'd been banned for six months a year ago for, you guessed it, cheating. So I calmly told him "No, but the DCI did."
He continued pitching a fit, a judge had wandered over by now anyway, and I proceeded to combo off without the sheet to the delight of everyone watching. Apparently no one liked this fucker. He conceded when I asked him if he preferred to be Zenith'ed or Brain Freeze'd to death.