text: > But since God was going to use Judas's sin, it was ok to eat with him, unlike other sinners.
  
  Judas wasn't a sinner. He as an apostle who was going to sin.
  
  > So how does this affect the serving of the Eucharist? 
  
  Judas didn't betray Jesus until after the Last Supper, so this line of questioning really doesn't affect it. Judas left the Last Supper early to meet with the Sanhedrin. There is debate as to whether Judas received communion or not.
  
  > Is there a method to determine which sinners are going to be used by God, so they can be given a "Judas Waiver?"
  
  You are really stretching here to make up some rule. It is simple. Are you in a state of grace? Yes? Receive. No? Don't receive. What if you are not in a state of grace and you do receive? You have just committed another sin.
  
  Why is this difficult to understand?