That mechanism doesn't work when you are dealing with non payers that have low feedback to begin with. Every non payer starts somewhere.....

LOL, yes... but it's repeat habit that is the most worrying. Everyone can make one mistake. Do the wrong things often and you're asking for trouble. Sometimes it may be unavoidable and in those times, the non-payer should contact the seller to explain their situation. A little communication can go a long way on both ends.