Scouts certainly can be and many are registered members of more than one Troop!
I know of several Scouts that are. When I found out about the other boys I called the Council HQ because I thought that would work quite well for my Sons situation.
They responded in a rather routine tone about it, and said to simple write "Multiple" on the top of the app. for the additional Troop.
They said that one Troop would be listed as primary but that it really had no bearing on anything, such as, Scouts could still do rank advancement with either or both Troops.
They went on to say that although it m