Regardless if it's "ethical/fair" or not (and it's really concerning that you're conflating the two words) it's still illegal and you can get hit pretty hard for it. Saying it's ethical doesn't get you out of court or a hefty fine.

Give me an example of something that is ethical but unfair, or fair but unethical

https://en.wikipedia.org/wiki/Judgment_of_Solomon is unethical but could be considered fair (with respect to the putative mothers, if not the baby).

A fascinating story!

Feel free to use ethics as your legal defense when you get sued... as for me, I'll stick with a solution that's both ethical and legal.