Downgrading packages after removing a repository

[Andrew Sayers]

Michael Bienia wrote:
<snip>
> Indepenent of how hard you make it to break an installation, there will
> be someone who managed to break it nonetheless and expects from you to
> unbreak it. And at the same time you will annoy experienced users who
> know what they are doing.

I don't follow this part.  Could you explain how the proposed solution 
(warnings on upgrade, warnings on downgrade) increases the number of 
people who expect Ubuntu to unbreak their system, or the number of 
annoyed experienced users?

	- Andrew