Silmarillion - Chapter 10 - Of the Sindar

[Raynor]

Originally Posted by Squatter

For this to happen the Sindar must be dispossessed

Well, even from Thingol's words we can see that he acknowledges the presence of "empty and wild" lands. The only dispossession that occurs would be a theoretical one. That is, in case any Sinda thought that all the land was rightfully theirs to begin with, regardless whether occupied or not, which would seem quite against the respect of Nature that the elves seem to inspire. If Thingol claims any rights, it is mostly concerning his people and where they actually dwell.