Now children, which would you like? A silly old time capsule or a lollypop? Can hear the squeals for lollypops from here.

Well indeed. In fact a further exploration into the workings of the average junior mind might throw the "disappointment" defence into even sharper relief.....
Exactly how old does a child have to be before it starts to think there's the slightest difference between "we're sending your painting to the future by putting it in a hill" and "we're sending your painting to the future by putting it in the ground" ?

Older than me and thee, evidently, so is the claim just a tad lacking in sincerity?