what happens??? a small somalian child dies...thats what happens.......
actually...its not good to block both breathers...thats why they are called breathers....its part of the crank case ventilation system..you block them off and the vapours caused by the cavitating oil in your sump will try and find the easiest way out...which means your timing cover and rear main oil seals will be the first things to leak....
actuall it surprises me how coherent i am this time of the morning without my coffee