From Test-Scratch-Wiki

The Account Deletion confirmation message.

Account Deletion is a feature that was added on December 1, 2014. It is used if a Scratcher wants to delete their account.[1]

Warning Warning: Do not play with this feature. Your account could be permanently deleted. Deleted accounts cannot be recovered.
When you try to logon to a deleted account.

Instructions

The Account Deletion link.

You can delete your account by going to your Account Settings and clicking "I want to delete my account". You will then be shown some of your projects and followers to make sure you want to do this. You then will have two choices to either delete your account AND projects or account but not projects. If you continue, your account will be placed in a 48-hour "scheduled for deletion" list. If you log on within that 48 hours, your account will be removed from this list. If you do not log on within 48 hours, your account will be permanently deleted. You must know your password to delete your account.

Bans Leading To Account Deletion

See also: Ban

Bans are normally just temporary, but if you do the same thing to break the Community Guidelines constantly, or what you have done is very severe, your account may be deleted.[2]

References