Yes in a modern society there should be ethics and morality, and DU is right there are many laws about that, go back and study labor in business, people had to fight for an 8 hour work day, 16 hours was not unheard of in the 1800's and early 1900's. I don't think this example is really about that, the op did not give enough info to make any moral decision.
The same scenario with different variables can affect things in any scenario.
If I am walking down the street clearly see someone reach into their pocket to get their keys and a wad of money falls out of their pocket, and they keep going, I am picking that up and saying "Excuse me, you just dropped this" I think that is the right thing to do, someone else can feel differently but that does not involve me.
If I am walking down some dusty trail with no one around and see a wad of cash on the ground, morality does not play into this. There is literally no one on this trail, no business right outside of it, its just money on the ground. Picking that money up is not immoral.
So someone just regging a name out of the millions of names not knowing it was someone else's previous website is not making a moral decision, they just hand regged a name.
I have handregged a name and someone email me and explain it was their baby. They were out of the country for their day job and never renewed, they emailed me the original email when they regged the name years ago, same name and same address. I said I am not paying your renewal it was $8.50 send me that paypal and I will push you the name. They were overjoyed, thanked me, if ever in their state come for dinner, etc...
It was a handreg, it meant nothing to me a lot to him. IMO it was the right thing to do. I understand and don't look down on anyone wanting $1000 as an example, that's their business, and they have every right to ask what they want.