The validity of land ownership is contingent on the opinion of our neighbours

To know whether someone is trespassing we can only make reference to the opinion of the community. If the majority are of the view that a person is occupying land illegitimately claimed, then we can say that the person is trespassing. We are not trespassing if most people do not object to our having (exclusive) use of the land.

Since, if we have taken only a small quantity of land then we have, very likely, left enough to our neighbours, then we can suppose that most people will not object and we can own land when we have only a small proportion. We might face more strong disagreement if we have taken an excessive quantity of land. Our land claims will be less popular if we have taken an excess, and in this case, due to its unpopularity we will cease to be the legitimate owner of the land.

If we have not left enough (and as good) land to others then we have violated the Lockean proviso and we have more land that we are entitled to claim according to the Lockean limit. Land is not owned beyond the Lockean limit because this will cease to be with the consensus of the group. They will then be trespassing on the land and it will be perfectly legitimate (under normal practices of arranging property rights) to remove them.

Land ownership will be unpopular beyond the Lockean limit and this will mean that the land ceases to be owned.