[Raapys]

Hmm, I definitely see your point in the spring and bullet scenarios, where it's obvious that there is energy waiting to be released, but with gravity too?

To clarify my question: If we had a device that could read the potential energy we're talking about, then that device would generally, in the case of a compressed spring, come up with the amount of energy used to compress it, right?
But would you also be able to "find" the ( potential ) gravity energy?

I guess my point is, isn't the potential energy of the spring real, i.e. it's actually in the atoms and can be measured, while the potential gravity energy isn't ?