> I can't intuit a significant bias, so I may well be wrong here Assume you have a deck of 3 cards. If you switch any 2 cards 3 times, you end up with 27 possi

> I can't intuit a significant bias, so I may well be wrong here Assume you have a deck of 3 cards. If you switch any 2 cards 3 times, you end up with 27 possibilities. But there are 3! (= 6) permutations. Obviously 27 isn't evenly divisible by 6, so some permutations are represented more than others. It's not as big an issue, but it is an issue, and it's a mistake many people are likely to make.