[logfromblammo]

For us? None.

We store reduced-precision, reduced-accuracy copies of the mass data wherever we keep the logs for our measurement devices. We can't get at the "real" numbers, anyway, so we just go by what our instruments say.

We can, however, "write" to the real data store for mass--by doing things like picking up rocks and throwing them. If we are living in a simulation, and it is imperfect, we could potentially exploit an imperfection by manipulating the simulation in just the right way.