You will need anyone in your party (at least their magic bands) with you to be linked to the
DAS. Even if you get the DAS first, you will need to go back to Guest Services to link the others in your party.
I will say that last trip they asked each one in our party in person to scan their bands. I don't know if it's some sort of crack down to make sure that people aren't double dipping (not even sure how that would work), but when I tried with just the bands, they asked to see each person before they were added.
It did not happen the trip before and I don't know if it was just our cast member (always a possibility - consistency is not always a strong suit at GS) but did want to bring it up.