Let me explain ban transitivity in our tiering system using Rowlet Matryoshka.
Now, the first Rowlet represents every possible game you could ever have in 1U, the second Rowlet represents every possible game you could ever have in 2U, and so on. Because our bans are transitive, the second Rowlet can always sit inside the first Rowlet, the third Rowlet can always sit inside the second Rowlet and so on.
But what if we had a non-transitive ban, such as banning Wrap in 2U and then allowing it in 3U? Then the third Rowlet streeeetches out its wings, and now it can't sit inside the second Rowlet.
Luckily, in our system, we don't allow non-transitive bans, so the Rowlets never spread their wings and they can sit inside one another!
Now, the first Rowlet represents every possible game you could ever have in 1U, the second Rowlet represents every possible game you could ever have in 2U, and so on. Because our bans are transitive, the second Rowlet can always sit inside the first Rowlet, the third Rowlet can always sit inside the second Rowlet and so on.
But what if we had a non-transitive ban, such as banning Wrap in 2U and then allowing it in 3U? Then the third Rowlet streeeetches out its wings, and now it can't sit inside the second Rowlet.
Luckily, in our system, we don't allow non-transitive bans, so the Rowlets never spread their wings and they can sit inside one another!