In December we have an extended family cruise with almost everyone getting something different. We'll have 1 DBP, 2 RP, 1 SP, DW will use her diamond vouchers and 1 who will just want a couple Latte's a day so I'll buy that for her with my Diamond vouchers. And finally, one who wants nothing. The only requirement is when someone want the DBP. Then all other adults in the room need to get it or the RP in lieu of the DBP.
There's no requirement for anything for any kid.