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: 
You can play a Wild card on top of *anything*, so long as it's your turn to play. Your friend is crazy. 

For the Wild Draw 4, you should ideally be unable to match the color - it is possible to challenge a Wild Draw 4, and if the person who played it could have played a card to match the color instead (not the number), the person who played it has to draw the 4. If the challenge is wrong, the challenger draws 6 instead of 4.
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.