Joseph, I'm not aware that any tribe SOLD their land, or that this sale was via a transfer of Land Title under the then US law, because IMHO the US Government didn't recognise Native Title, and for that matter Native tribes had no citizenship until 1924, so neither individuals, nor collective legal entities could make a contract recognisible in US civil and administrative code.

It seems the USA is a state created on stolen property, though some of it was not originally stolen by the USA. Europeans would claim land under Right of Conquest.

What are the Imperium policies towards indigenous planetary sapients that decline to integrate?

Cheers

Greg