ignatius - what if you lived in a 3rd world country, and you asked your neighbor to help you erect your stick and hay roof on your one story mud hut, should the neighbor have 1/2 a right to the utility of your mud hut because that stick roof exists only because of the neighbors aid? That is the same math applied to a different situation.
And, the moral objection is covetousness. You are coveting that which doesn't belong to you on perhaps multiple levels.