Often the case with these dungeon architects. Thoroughly bonkers. The bigger the dungeon the more bonkers the architect, usually. Must be vitamin D deficiency or something.Given that whoever created the statue in the first place seems to have been a bit kooky in the head*, I'm not sure "fair" enters into it.
I believe it is reasonable even if that were the only way to open the chest.
I don't disagree with you, Dausuul. However, given the nature of the goblet in the first place, it would not be untoward to have a chest that is similarly magical.
That said, I always assume that "Only way" is GM-speak for "The only way that the designer of the scenario could think of" and reward imaginative means to do anything.