If it only takes 30 seconds, why not do it on the ground while they are preflighting?

I'm sorry you think caring about the safety of the people paying you (or expecting you, in the case of a safety pilot) to ensure their safety is being on a "high horse". Obviously, I can't be looking for traffic 100% of the time, but to purposely plan on reading a POH while the other pilot is under the hood is reckless at best.

Having had a few near misses, I realize the importance of looking for traffic.

If my CFI started reading a book while I was under the hood, the hood would come off and it would be their last flight with me.