The rules can include "on failure" actions, I suppose.
Yup, that's what I thought, too.
Probably the local system should be able to override that.
Why? Do you have a specific example in mind? Maybe I misunderstood
you, but I would think that it's up to the user (i.e. the rule
"owner") to specify what happens in case of a failure. For example,
the user has to decide whether she/he wants to receive a file download
if the callout to a virus scanner fails. This is the decision of the
user, the local system must not override that.