Agree. I would not count on doing it unless eveyone was present.
In late October 2019, when we set up our daughter’s
DAS, we tried to add our friend who was not with us. We had his Magicband, but were told he had to be with us.
The next time we tried to add him, my husband our friend had gone to Epcot early while DD and I were arriving later. My husband tried to add our friend, but was told our daughter needed to be there Aldo.