I was told at the Visitor Center (without asking) that, should your group separate on the trail, you show your wag bag (used or unused

) to the ranger and simply provide the leader's name and approximate location.
How they're supposed to enforce that particular method isn't really clear nor is it our problem. They seem to be extremely lax this year and last...
Edit: It may not hurt to have the ones going to the summit carry the permit, regardless of whether they're the leader or alternate.