Don't frame it as "build an illegal feature". Frame it as "build a feature" and hand it off to an enthusiastic junior dev eager to please their manager and get ahead. At a previous employer, I had a manager ask if, when implementing certain functionality, I could do it in such a way that it coincidentally broke third party tools attempting to interact with the component. They were very careful to phrase this in an offhand manner and never discuss it over legally discoverable mediums (only face to face). The entire matter seemed dubious and I certainly didn't want my name associated with such a move in the source control history, so I never implemented that request, it was never mentioned again, and nothing ever came of it - but a different dev might have jumped much faster at it.