From the CQRS for dummies post we can extract a couple of important concepts.
Non blocking operations, we can continue to speak even when our conscience is gone.
Eventual consistency due to persistent storage of past events, the conscience was able to get back in synch without missing that we did break some of it rules.
Compensating actions do not have to put the system back in a consistent state. Your flowers might not be enough. Some events can simple not be compensated.
Building systems that meet these requirements are hard.
Applying Forget it ever happened is typical in conflict with persistent storage of past events.
A perfectly valid real world example of when we need Forget it ever happened is when, by mistake, we associate a person’s new hidden identity with his old identity in our database. Do you know how much fun it is building a bullet proof auditing system just to realize we need to erase a record in it?
Every time we by mistake reveal a secret; we would love to have the ability to forget that the thing ever happened.