If you default on your obligations, then you lose your shares ~ sorry no partial default. If you have 10, then physical delivery is good way to get out and still meet your obligations; and still collect on the Neptune.
Is there any possibly this policy could be amended. I am thinking worst case scenario were the Neptune does not arrive in time and ANTMINER S1 becomes unprofitable. In this situation we would forfeit our mining rights before we get a chance to mine with the Neptune(Resulting in only 18GH per share instead of 30GH) or choose to mine at a lose while waiting for the Neptune to arrive. Also, since we are already paying you separate mining fees for the ANTMINER S1 and Neptune this would not add much of a burden and will not take away from your finances. For me and other miners this would add addition peace of mind and would encourage addition purchasing of shares.