Yes, you can. As said, this option is only valid during initial MCC setup.
It just skips the check that both MDVs need to reside on different aggregates for redundancy purposes.
After the MCC has been configured, this option is of no use anymore. The MetroCluster as of today does not check where the MDVs reside after MCC has been configured.
There is a BURT open though for a future improvement to have ONTAP relocate one of the MDVs automatically, once a second aggregate is created.
Kind regards, Niels