[bingobangobongo]

This isn't really something we can try, but I suspect you'd get turned down some reasonable percentage of the time (2%-10%, say) with such an offer, by people who have "all the money they need." Since to me the utility of the first few million is vastly larger than the last 500 million, I'd offer 50% just to avoid that rare case.

[vacri]

If someone is turning down $50M because they have "all the money they need", why would they then accept $500M?

[overcyn]

The same reason, a normal person might decline $5 but accept $50 out of a pool of $100. 5% seems more unfair than 50%.

[vacri]

"i have all the money I need" is a different reason to "that's hardly fair!"

[qu4z-2]

It's the combination of the two, I think.

That's hardly fair... but I need the money => Accept.

I don't need the money, but it's fair => Accept.

It's unfair, and I don't need the money => Turn down.