If land isn't claimed, isn't being used, and he lays claim to it for a period, then the wasteland can become his if he fulfils the criteria, but I sure as hell don't want his mud hut on my land, I paid for it, and it is costing me dear.
Don't think that bit is true any more. I don't remember when, but recently they abolished squatters rights completely and made it virtually impossible to claim unused land through occupancy alone.