Donald,
We then have the identifiers I1 and I2. In different situations these may serve as identifiers for O1 and O2 or for D1 and D2 or for D1+M1 and D2+M2. None of these is necessarily right or wrong. Appropriate practices must be defined in each case.
It is "wrong" to interprete I1/I2 as identifiers of O1/O2. They could be identifiers of Ds or D+Ms, but shouldn't be ID of Os. Isn't it our agreement at very early stage of this list?
Interpretation of I1 and I2 is responsibility of applicagtions, not of GUID itself. What we need to decide is D or D+M, not O.
I dont have sufficient time to spend on this issue at this moment for taching biodiversity informatics to undergraduate students, so I hope I didn't miss some important assumption already mentioned on the list...
Cheers, James