...Why? "Hmm, yes, let me just lock away this 5g in a chest with the best lock I can buy and hide where nobody can find it!"
Ah, but you - and by "you" I mean the gameworld character - doesn't know:
A. what's in it BEFORE you open it
and
B. whether there MIGHT have been something more useful in it not that long previously - absence of evidence is not evidence of absence.
As you might have guessed We go with option B - IRL just because there is nothing in my fridge when I open it, doesn't mean there was NEVER anything there. I'm fine with that.
Actually if I am honest, I would rather NOT be told that something is empty. If I could mod that notification out, I would...