[AtlUmpSteve]

I'm pretty confident that taking away the strategic option available to the offended coach will result in an angry reaction and likely confrontation; I know of several instances where coordinators were called with complaints about this.

Preventative officiating ends where you give one team or coach a competitive advantage without language telling you to do so. Refusing to accept an illegal substitution is very different from pointing out one that is legal as reported, but implemented illegally, and blatantly assisting the opponent to secure a better outcome.