Eh, that isn't that important though. They can choose to feel however they like and a skilled negotiator could frame the request well. The question is really "would they pay?".
Now, the real question is: how does a skilled negotiator frame “pay me $1000 and I’ll leave tomorrow” in such a way that the landlord feels like a hero for complying? With a neutral third party suggesting this, it is pretty easy as OP post suggests, but if you're the tenant suggesting that I think it won’t be as easy.
It really isn't. They're a landlord. If one option loses them less money they'll pick that option. The finances will win because they're not putting the house on the market to get warm fuzzy feelings. If they've been a landlord for even a small number of tenants they're used to outrageous demands and know how to take them in stride.
They're more likely to accept the frame if it is nicely presented, but at the end of the day they'll swallow their feelings and choose the cheap option unless a tenant is being an outrageous bastard about the whole thing.
I agree that their feelings are important. But their finances are really the guiding star for their decision making.
It's a nice idea to think human beings are strictly rational, but they aren't. We've long known, homo economicus had his funeral in the 90s. Amos Tversky murdered him in an entirely rational way.
OK, kidding aside - purely rational decisions are extremely rare.
> but at the end of the day they'll swallow their feelings
People do many things, but they very rarely swallow their feelings. If you've ever seen a neighborhood lawsuit or a divorce, you've seen feelings be extremely powerful things, even if finances are involved.
"unless a tenant is being an outrageous bastard" is the operative phrase there. Feelings color what's considered outrageous. Sometimes, "he looked at me funny" is all that's needed to make an entirely irrational decision.
There's a whole bunch of studies clearly showing that people would rather take a monetary loss than a gain where they think the other party gets an outsized gain (not at their expense) as a result in the latter case. Humans are weird. Feelings matter a lot.
One of my favorites is this one: https://www.sciencedirect.com/science/article/pii/S016726819...
One of the examples in there is a choice about pay at work
A: You make $50,000; others earn $25,000
B: You make $100,000; others earn $200,00
And a very large number of participants would rather choose A, because that means they'd be relatively better off than their colleagues. Even if they end up with half the income.
He ran it for years.
You can even make (somewhat slimy) money by identifying these situations; there's money to be made in spiteful divorces, for example.
"Honestly, I'm worried I can't afford to move, you're a smart guy, I bet you're worried about that too. I get it, I don't want to be 'that' tenant." (label the negative emotion, empathize)
"How am I supposed to move so soon? It'd cost me $1500 and I can barely even afford the rent." (Anchor a price, turn it into problem solving)
"This is probably going to sound unreasonable, but could you help me with the move? That way I can be sure to be out on time." (Calibrated question to guide the conversation)