Leaving off failed degree off of resume

I applied to a lateral hire at a regional firm, which only took my resume and accepted me for further tests and interviews.

• So far I've asked several forums whether I am allowed (legally and ethically) to leave off an incomplete/failed graduate degree on my resume, and the consensus was generally yes, unless an application to the job explicitly asked me to list all educational history without omission.

• Since I am a lateral hire there was no formal application process; I only submitted a resume, so I was never asked to list all degrees attempted and/or enrolled.

• So do I need, usually, to include degrees that I attempted yet didn't graduate? What about distance programs that only require you to sit an exam at the end of the study period, which I never sat for?

Thanks.