ECB provides confidentiality, but not integrity or authentication, when the message length is always exactly one block and messages will never be repeated with the same key. These circumstances are rare but not unheard of. For instance, in a protocol intended to be used under steganography, you want every bit of the ciphertext to be indistinguishable from randomness; one way to achieve this is to use a normal authenticated mode for the message proper, but then encrypt the IV with a second key, in ECB mode. You can fix the length of the IV to be the underlying cipher's block size, IVs shouldn't ever be repeated anyway, and integrity and authentication are not needed because the message proper will fail to decrypt if the IV has been tampered with. Doing this without giving the adversary any sort of oracle to work with adds a few complications, but that's the basic idea.
However, because you are always encrypting one-block messages with the second key in this scenario, it's equally accurate to say that you are not using any operation mode; you're just using the block cipher. And to avoid people seeing "ECB mode" and jumping to the conclusion that your protocol is garbage, that is how I would recommend writing it up.
(The second paragraph of this answer is paraphrased from something Dan Boneh told me about six years ago.)