Sneak attacks vs Concealment, balance or common sense ?

[Plane Sailing]

Probability does not work that way though.

Each and every roll is a new one for determining actual probability.

If you had a percentage of a number like for sales tax or something like that you would be correct, but not for probability.

Oh yes it does! (oh no it doesn't!). I love pantomime, but really

It sounds to me that you are mixing up two concepts in probability.

e.g. the chance of rolling 18 on 3d6 is 1 in 216 because you have to roll 3 dice and get 3 sixes. The probability is 1 in (6 x 6 x 6) = 1 in 216.

For any given roll of the dice, the probability of a particular number is independent of all the rolls that have gone before it... but we are concerned with the overall probability of an event occuring that depends upon the result of those multiple die rolls.

If you don't believe me, pick up those dice and simulate 1000 attacks upon a foe as if you have Blindfight. I'd be most surprised if your end result didn't come out pretty close to 40 total misses in that experiment i.e. effectively 4% miss chance.

I am reminded of the complete pigs breakfast that the writers of Sword and Fist made when attempting to discuss the probability of using flurry of blows. The rules are pretty simple when it comes down to it, but I still see people get confused all the time.