Specifically thought about this in relation to their subscriptions, however in thinking more I realized that foreign key constraints have not been set on non-polymorphic relations as well.
Although the feature to delete your account has not been added yet it is important to note that when this feature is added to use a combination of model events (for polymorphic relations like subscriptions and notifications) and foreign key cascading for non polymorphic entities to accomplish this.
Specifically thought about this in relation to their subscriptions, however in thinking more I realized that foreign key constraints have not been set on non-polymorphic relations as well.
Although the feature to delete your account has not been added yet it is important to note that when this feature is added to use a combination of model events (for polymorphic relations like subscriptions and notifications) and foreign key cascading for non polymorphic entities to accomplish this.