also, knots is simply not relaying transactions the filter settings say are spam.

once they get into blocks they accept them, and i think it can also be set to not relay those blocks for a while, like first or second block have to go on top before it will start relaying the block.

it happens fairly often, like every few months that there is two blocks competing to be at the top and settings like this would favor the block that didn't have as much spam in it.

it won't cause a fork but it may reduce spam, slow it down, and favor legitimate use.