I don't know about this, really. I have never heard people talking about their ad unit ids, so I think it is kind of "private" and should not be disclosed?
Is my ad unit ids a piece of private information? What will happen if I do disclose my id? Is it ok?
Yes, you should never share it with anyone or post it online. Someone could use your Ad Unit ID to spam requests and get your AdMob account flagged or banned.
Your Ad Unit ID also contains your AdMob developer ID. For example, ca-app-pub-[developerID]/[adID]. I'm not sure how that information could harm you exactly, but it is unique to you.
来源：https://stackoverflow.com/questions/36967604/is-my-admob-ad-unit-id-a-piece-of-private-information