Question: The card Clerical Error has the text:

> 
> Choose a player. Collect any noble of your choice from that player's
> score pile. That player then chooses any other noble from your score
> pile and collects it.
> 
> 
> 

The noble Robespierre has the text:

> 
> The day ends after you collect this noble. Discard any nobles
> remaining in line.
> 
> 
> 

According to [this thread](https://boardgamegeek.com/thread/217462/offical-guillotine-faq) on their interaction:

> 
> Clerical Error would work just fine, but end the day and discard all
> nobles in line if used to get Robespierre from someone else's score
> pile.
> 
> 
> 

This seems to imply that noble abilities continue to work from the score area, which seems consistent with nobles like the Palace Guards, whose abilities must work from the score area. So, two-fold question:

1. Does this mean that if I use Clerical Error to collect someone else's Rival Executioner ("Collect the top noble of the noble deck after you collect this noble"), I get that ability? (I'm guessing yes)
2. Why doesn't the Master Spy ("After each action card is played, move this card to the end of the line.") move to the end of the line from your score area if anyone plays an action?

To put it differently, what rules framework can we construct for Guillotine about what types of abilities work in what zones of play to get the desired behavior?

Answer: 
A common Uno variant allows the recipient of a draw 2 to avoid drawing (and being skipped) by playing their own draw 2. The next player either needs to skip their turn and draw 4 cards, or play their own draw 2. If they play their own, the next player must either draw 6 cards or continue the sequence. Some variants allow similar behavior with draw 4 cards.

Assuming you're talking about this "stacking" draw cards, you aren't going to be able to get an official answer, because it isn't an official rule. This would explain why you and your friend are both adamant about it working in different ways. You're just going to have to come to an agreement on how you will play.

For what its worth, every place that I've seen this rule described you have to play the exact same card, so you cannot "stack" a draw 4 when receiving a draw 2 in order to make the next player draw 6. So I expect that is the more common way of playing the variant.
According to this link (<http://www.qcsalon.net/en/uno>), a +4 can't be played on top of +2 or vice-versa. There are other rules too, regarding playing of a +4 card, you can choose to follow.