I don't think I was clear in my original post. I see in the rule book example exactly what you're saying. My point is that no other action or game phase works like this. The whole thing behaves like a response, but it's labelled an action.
If I can play actions after revealing my top card during a burgle attempt, what's stopping me from playing Gandalf's Search right then? I'm guaranteed access to the top card, which by definition matches the top card. Same thing with using Berevor to just draw the top card immediately after I reveal it for the burgle attempt.
Good point. I can see errata coming to the Lonely Mountain.