In Reply to: But it must be purchased posted by Tinkerbell on Tuesday, 9. December 2008 at 07:34 Bali Time:
that the person purchasing would be one of the adults.
I am not sure what is stated on the declaration card that you fill in on the plane before arrival, but if there is no reference to age etc. then I would fill in a seperate card for the lad, and give it a go.
You have complied with all legal requirements that can be reasonably seen, and the worst that can happen is that you can offer to forfeit the bottle if challenged.
I doubt that this exercise will turn the 17 year old into a hardened criminal, and I expect that he has better ideas on how to go about this sort of thing than me.