Twitter should automatically and quickly delete your tweet if it is bad.

The idea is to specify some criteria as to when twitter would automatically and quickly delete your tweet.

For example, if more than 2 people unsubscribe soon after your tweet is posted, then delete it automatically to avoid further reducing your audience.

You can even be more specific by only considering unsubscribers who pass some threshold in that count (e.g., those with at least 1000 followers).

Moreover, your criteria can take into account retweets and new subscribers.

CLARIFICATION: You -- not twitter -- would specify the criteria for automatic deletion of your tweets. If you don't like this feature, then don't use it.