Chance of 3 cards same suit on flop if you are not holding any and you don't put anyone else on a flush draw:
12/49 (chance of 2nd card being same suit as 1st) x 11/48 (i.e. 11 remaining cards of that suit / 48 cards left)= 132/2352
Chance of turn being same suit also:
132/2352 x 10/47 = 1320/110544 which is approx. 1.2% chance
If I've made any mistakes, hopefully some maths whizz will come along and correct me.
Can't think why this stat would be useful though. Hope you're not drawing to flushes with off-suit cards.
Thanks for this.
Quite the contrary actually. Without getting into any mythical debates about site software I've been killed no less than 21 times in approaching 400 sit and gos at Stars when all in by runner, runner, runner, runner flush.
It's rather annoying when your trip Kings get trashed by a guy holding the three of diamonds in his hand and down they come, one by one.
Actually I nearly smashed my screen yesterday it was so annoying

If you had an unbiased sample of 400 preflop allins where your opponent had unsuited hole cards and you lost 20 of these to 4 flushes, it would indicate non-randomness. However, I doubt that this is the case.
Most of these "exercises" are conducted when ppl are running bad - so the sampling is flawed. I suspect also that these are not all pre-flop allins, you have to consider that a backdoor flush might be factored into someones flop call, so that changes the probabilities.