Just wanted to note that this is an example of something I consider to be perfectly legitimate use of "common sense" and "[GM's] instinct"--not because it's about drama, but because there are guidelines. The rules specify the context and appropriate ranges; the GM is expected to use these judiciously, because the books can't do that part. They can furnish you with the tools to make those decisions easier, and to ensure that the impact of those decisions is worthwhile to the players. But they can't actually make the decision on your behalf, and do not try to do so.
I, as a player, can see and know the same rules and limits, the same structure, that the GM does. That means I actually have the ability to understand what processes are involved, what kinds of choices are being made in a given context. That means I can decide for myself whether the GM's judgment is judicious or not, whether or not their common sense is in fact common between us and actually sensible. I'm not dependent on trying to read someone's mind when they're making decisions inside the black box that they won't describe to me (and that I would not want them to describe to me in that context, to be clear!)
This is strongly related to my...intense...negative reaction to the suggestion that players should have all of the rules hidden away from them, so that they are wholly dependent on the GM telling them what they can or cannot do, what is or is not possible, etc., etc., without any means, whatsoever, of knowing what is happening within the rules. I find that particular concept...let's just say "off-putting" would be the understatement of the decade.
Players knowing the frameworks in which decisions are made, understanding where the boundaries lie, is quite important. Hence why I have a rather dim view of the idea (I don't think Gygax said this one?) that you should forbid players from playing in your game if they've read the DMG.