Original poster here. The question was specifically about summer camp (wasn't sure if the regular troop positions automatically extended to camp). The ASPL boys who were "passed over" for leadership at camp were taken by surprise to be told (at camp) that they would not be SPL and ASPL for the week. They accepted the authority of the (new) leader who did the assigning.
@ CalicoPenn -- Agreed! They'll get over it. All part of the learning.
@ Senior Member - Thank you for "The key really is that this is a choice made by the boys" -- and a good reminder to carry and use the handbook!
@ BSA