What rule are you citing that allows this? Remember, we're talking about something allowed by a specific ability, not players just randomly trying to weasel past obstacles.
No. That's not how specific beats general works. A rule is "general" until something acts to supersede it. The general rule of nobles is that they can get put up by local nobles. This is superseded by the DMG quotes that SPECIFICALLY state that rules in the PHB are secondary to DM rulings. He is not beholden to such rules. For something to overrule the DMG quotes, it would have to specifically say so. Nothing in backgrounds(or any other rule) does say so, so there is no such thing a specific beating the DMG quotes.
I gave an actual play example that wasn't ridiculous in any way. I prompted the player to tell me. The player is a creative guy, and he responded to the challenge and came up with an idea. And the result was something none of us had foreseen. The game went off in a new direction because of his ideas.
Also, you're now starting to veer into value judgments, which seems unnecessary.
Seeking to always say yes diminishes agency. It overrides those times when player agency is respected by saying no and instead says yes. It's not a value judgment. It just is what is. You can't seek to say yes to me all the time and have my ideas mean much at all.
But you said that requests may not work due to things the players didn't know. Like the no-healing god thing... give an actual example along those lines. I can't believe that this has never come up in your games, or else why would you be so adamant about it.
Yes, exactly. Give an example of that.
In full disclosure I have ADHD and my memory doesn't work normally. I've never been able to pull up examples just because. If something happens to remind me of the time we did X, Y to accomplish Z, it's there. But if I'm just minding my own business typing here, it's extraordinarily rare for me to be able to pull up that specific memory.
I can give an example from my most recent campaign when I allowed something reasonable even though the rules said no, because it's reasonable and I absolutely hate that many spells and magical effects will work on a stone golem(because creature), but won't work on a stone statue(because not creature).
Why are the players being sent to a different universe? Did they just get zapped there because the DM decided that's what happened? Or did this happen as a result of play?
Why does it have to be one or the other? It can be both. The DM could decide to have a portal like the City on the Edge of Forever that runs through images from various universes. The bad guy could jump through to escape. The PCs could jump through afterwards and roll poorly, ending up in a random universe. The DM decided AND it happened through game play.
It absolutely is inherent in yes or no.
This is an objectively false statement, because my agency can be diminished by both yes and no, and it can be respected by both yes and no. It quite literally cannot be inherent AND still allow that to happen.